Magazine-Based Data Cartridge Library

ABSTRACT

The present invention provides a magazine-based data cartridge library that, in one embodiment, comprises a plurality of shelves that are capable of holding a plurality of data cartridge magazines, one or more drives, a magazine transport for moving magazines within the cabinet, and a cartridge transport for moving data cartridges between a magazine and a drive.

FIELD OF THE INVENTION

[0001] The present invention is directed to a data cartridge librarythat is useful in storing data on a recording medium located in acartridge and/or retrieving data from such a recording medium.

BACKGROUND OF THE INVENTION

[0002] Presently, data cartridge libraries are primarily used to archivedata, i.e., store data that is not immediately needed by the hostcomputer, and provide archived data to the host computer when the datais needed. To elaborate, the typical data cartridge library receivesdata from a host computer and causes the data to be stored or recordedon the recording medium located in one or more data cartridges. When thehost computer requires some of the data that was previously stored in adata cartridge, a request for the data is sent from the host computer tothe library. In response, the library identifies the data cartridge(s)in which the desired data is located, retrieves the data from therecording medium within the cartridge(s), and transmits the retrieveddata to the host computer system.

[0003] Presently, most data cartridge libraries are comprised of: (a) aplurality of storage slots for holding data cartridges with the slotsbeing in fixed locations during operation of the library; (b) one ormore drives that are each capable of writing data onto the recordingmedium located in a data cartridge and/or reading data from therecording medium located in a data cartridge; (c) a cartridge pickerdevice that is capable of moving individual data cartridges between theslots and the drives; and (d) an interface for receiving data from andtransmitting data to a host computer. Such libraries are considered tobe “cartridge-based” data cartridge libraries (hereinafter referred toas cartridge-based libraries) because, during operation of the library,the movement of cartridges to and from the fixed storage slots isaccomplished solely by a cartridge picker device that transportsindividual cartridges. Generally, the operation of a “cartridge-based”library involves using the cartridge picker device: (a) to move acartridge from a fixed storage slot to a drive so that data can beeither written on to or read from the recording medium in a cartridge;and (b) to move a cartridge from a drive to a storage slot.

[0004] One approach to implementing storage slots in a “cartridge-based”library is to create a wall with a number of fixed slots. This approachhas a distinct drawback when adding cartridges to the library andremoving cartridges from the library. Namely, the fixed slots requirethe cartridges to be loaded into the slots one at a time and removedfrom the slots one at a time. This drawback is particularly acute insituations in which a library has a large number of slots and a largenumber of cartridges either needed to be inserted into or removed fromthe slots. An example of such as situation is when the library is beinginitially populated with cartridges. In such situations, an operatortypically powers down the library and inserts the cartridges into theslots by hand.

[0005] Another approach to the implementation of storage slots in a“cartridge-based” library involves the use of a data cartridge magazinethat an operator can mount or de-mount from a wall in the library.Typically, the magazine is a box-like structure that has an open sidethrough which cartridges can be inserted into and removed from themagazine, a partitioning structure that defines a number of slots forholding data cartridges, and a mounting structure that allows themagazine to be mounted and de-mounted from a wall in the library. Asignificant advantage of the magazine approach is that an operator, bymanipulating magazines rather than individual cartridges, is able tomore quickly insert a large number of cartridges into a library and morequickly remove a large number of cartridges from a library. However,regardless of whether cartridges are being inserted into or removed fromthe library, the operator is still typically required to power-down thelibrary or otherwise disable the cartridge picker device to avoid beinginjured by the device during the mounting or de-mounting of a magazine.

[0006] In many instances, only one data cartridge needs to be eitherinserted into or extracted from a “cartridge-based” library. In theseinstances, the powering down of the library or disabling of thecartridge picker device so that an operator can insert or extract thecartridge is undesirable. To address this situation, many“cartridge-based” libraries employ an entry/exit port that allows anoperator to insert a single data cartridge into the library and extracta single data cartridge from the library without being exposed to thecartridge picker device. Because the operator is not exposed to thecartridge picker device, the library does not need to be powered down orthe cartridge picker device disabled during the insertion or removaloperation. Generally, the entry/exit port is comprised of a slot forholding a data cartridge and a device that places the slot in one of twostates. In the first state, the slot of the entry port is exposed to theenvironment exterior to the library such that an operator can access theslot. When the slot is in the first state, the exit/entry portsubstantially prevents an operator from accessing the interior of thelibrary by way of the slot and, as a consequence, prevents the operatorfrom being exposed to injury by the cartridge picker device. In thesecond state, the slot of the entry/exit port is exposed to the interiorof the library such that the cartridge picker device is able to accessthe slot. When the slot is in the second state, the entry/exit portprevents an operator from accessing the interior of the library via theslot. For the insertion of a data cartridge into the library, the slotis placed in the first state and the operator inserts a data cartridgeinto the slot. The slot is then placed in the second state to make thecartridge available to the cartridge picker device for placementelsewhere in the library. For the extraction of a data cartridge, theslot is placed in the second state and the cartridge picker deviceplaces a cartridge in the slot. The slot is then placed in the firststate to make the cartridge available to an operator for removal.

[0007] Entry/exit ports that provide the ability to insert multiple datacartridges en masse into a library and extract multiple data cartridgesen masse from a library are also known. Such exit/entry ports aretypically employed in libraries that have a relatively high number ofslots and are used in a manner in which the insertion and/or extractionof several cartridges at a time is desirable but the powering down ordisabling of the cartridge picker device to allow a manualinsertion/extraction of the cartridges is undesirable. For these typesof libraries, the operator is effectively limited to inserting andextracting data cartridges via the entry/exit port. To provide theoperator with the ability to insert or extract several cartridges at atime, the entry/exit port has multiple slots that form a fixed part ofthe port. Alternatively, an entry/exit port is provided that allows amagazine with multiple slots to be inserted into the port by theoperator. With respect to this type of entry/exit port, insertion ofmultiple cartridges into the library is accomplished by placing the portin a first state so that an operator can either: (a) populate a magazinethat is already present in the port with multiple cartridges, or (b)place a magazine and accompanying cartridges into the port. The port isthen placed in a second state so that the cartridge picker device canindividually move each of the cartridges in the magazine to otherlocations within the library. To extract multiple cartridges, the portis placed in the second state and the cartridge picker deviceindividually moves cartridges from various locations in the library tothe magazine. After all of the cartridges that are to be extracted havebeen placed in the magazine, the port is placed in the first state. Oncein the first state, an operator can either individually removecartridges from the magazine or remove the magazine from the port.

[0008] In many applications, the user of a cartridge-based library has acurrent need for a library with a particular data cartridge storagecapacity and/or a particular number of drives but anticipates that therewill be a future need for a library with a greater data cartridgecapacity and/or greater number of drives. To address this situation,cartridge-based libraries have been developed that allow the user toinitially acquire a library that satisfies the current needs and whenfuture needs exceed the data cartridge and/or drive capacity of thelibrary, allow the user to expand the library. Certain cartridge-basedlibraries that have this expansion capability expand the library with aunit or units that expand the library horizontally. Othercartridge-based libraries expand the library in a vertical fashion. Ineither case, such cartridge based are in many cases able to passcartridges between the original library and the expansion units byexpanding the cartridge picker system.

[0009] In certain cartridge-based libraries, the use of expansion unitsthat provide greater data cartridge storage capacity and/or a greaternumber of drives and an expandable cartridge picker system is notpracticable. For instance, the use of expansion units and an expandablecartridge picker system is typically not practicable for libraries thatemploy a cartridge picker system that traverses a circular path, whichare sometimes referred to as “silo” libraries. Nonetheless, in manysituations, there is a need to transfer cartridges between libraries forwhich the expansion approach is impracticable and to do soautomatically, rather than transfer a cartridge out of one library byits entry/exit port and then have an operator transfer the cartridge tothe entry/exit port of the other library. Consequently, cartridgepass-through ports have been developed that allow one library toautomatically transfer a cartridge to another library, i.e., withoutoperator assistance.

SUMMARY OF THE INVENTION

[0010] The present invention is directed to a “magazine-based” datacartridge library that is capable of moving data cartridge magazineswithin the library, as well as moving individual cartridges within thelibrary. A magazine-based data cartridge library (hereinafter referredto as a magazine-based library) is comprised of: (a) one or more shelvesthat are each capable of holding one or more data cartridge magazinesand allowing the one or more data cartridge magazines to be moved to andfrom the shelf system by a robotic device; (b) one or more drives thatare each capable of reading data from and/or writing data to a recordingmedium located in a data cartridge; (c) a magazine transport device formoving a magazine within the library, including the movement of amagazine to and from the shelf system; (d) a cartridge transport formoving data cartridges between a magazine that is moveable within thelibrary and one or more drives that are located in the library; and (e)an interface for receiving data from and transmitting data to a hostcomputer. In contrast, a cartridge-based library does not have theshelves or the magazine transport of a magazine-based library. Further,it should be appreciated that a cartridge-based library does not havethe cartridge transport of a magazine-based library. To elaborate, thecartridge picker in a cartridge-based library moves cartridges to andfrom slots that are at fixed locations during operation of the library.In contrast, the cartridge transport of a magazine-based library movescartridges to and from the slots of a magazine that is capable of beingmoved by the magazine transport device during operation of the library.

[0011] A magazine-based library has a number of advantages relative to acartridge-based library. For instance, in one embodiment of amagazine-based library that has multiple drives, cartridges can be“bulk” loaded into the drives. In a bulk load operation, an embodimentof a magazine transport device extracts a magazine from a shelf andmoves the extracted magazine to a location adjacent to the drives, whichare typically situated in a row or column. Once the magazine ispositioned adjacent the drives, an embodiment of a cartridge transportmoves a cartridge into one of the drives and then another cartridge intoanother one of the drives. The cartridge transport continues loadingcartridges in this manner until the desired number of cartridges havebeen loaded. In most cases, the total distance moved by the magazinetransport and the cartridge transport in performing a bulk loading ofthe cartridges will be significantly less than the distance that acartridge picker in a cartridge-based library would move in traversingback and forth between the fixed storage slots and the drives in loadingthe same number of cartridges into individual drives. As a consequence,with other factors being equal, this embodiment of a magazine-basedlibrary is able to load the drives faster than a cartridge-based libraryand in many cases, considerably faster.

[0012] One embodiment of the magazine-based library has a layout inwhich the space allocated to the magazine transport (i.e., the spacewithin which the magazine transport must be able to move within thelibrary to position magazines at all desired locations within thelibrary) has at least one dimension that is related to a dimension ofthe magazine employed in the library. To elaborate, when a magazine issituated on a shelf in a magazine-based library, the front and rearsurfaces of the magazine define a magazine plane with a depth that isequal to the distance between the front and rear surfaces of themagazine. The space within which the magazine transport operates is alsoa plane that will be referred to as a transport plane. The transportplane is parallel to the magazine plane and, like the magazine plane,has a depth. When the magazine transport removes a magazine from ashelf, the magazine transport displaces the magazine from the magazineplane into the transport plane. In one embodiment of the magazine-basedlibrary, the depth of the transport plane is greater than the depth ofthe magazine plane but less than twice the depth of the magazine plane.Typically, the closer the depth of the transport plane is to the depthof the magazine plane, the more likely the overall volume of spaceoccupied by the transport plane approaches an optimal volume at whichthe volume of the transport plane is the minimum needed to transportmagazines within the library. Consequently, a transport plane or spacewith a depth that approaches the depth of the magazine plane cancontribute to achieving a high data density footprint for the library.The data density footprint is the amount of data that a library iscapable of storing when the maximum number of data cartridges that thelibrary is capable of accommodating are housed within the librarydivided by the area of the floor space or footprint occupied by thelibrary. The depth of the transport plane is preferably less than about150% of the depth of the magazine plane and more preferably less thanabout 130% of the depth of the magazine plane. In a further embodiment,the distance between the front and rear surfaces of the magazine used inthe library or the depth of the magazine plane is roughly equal to thedepth of the drives used in the library, i.e., within about +/−20% ofthe depth of the drives. By employing magazines with a length or depththat is related to the length or depth of the drive(s) employed in thelibrary, the ability to layout the components of the library in a mannerthat efficiently uses the space within the library is increased.

[0013] Another embodiment of the magazine-based library is particularlyable to move magazines that are relatively heavy when fully populatedwith cartridges. To elaborate, this embodiment of the library comprisesa magazine picker for displacing a magazine towards and away from ashelf and an elevator for moving the magazine picker within the library(an elevator that moves in only one dimension or in multiple dimensionsis possible). To manage fully populated magazines that are relativelyheavy, the magazine picker is comprised of a support surface on whichall or a portion of a magazine can rest and a device that is capable ofmoving a magazine between a shelf and the support. In one embodiment,the support surface comprises a guide structure that serves to orientthe magazine during the transfer of the magazine to or from a shelf andto maintain the orientation of a magazine during movement of the supportwithin the library by the elevator. In another embodiment, the devicefor moving a magazine between the support and a shelf comprises: (a) anengagement device for establishing a connection with a magazine that issufficiently positive to allow the magazine to be moved; and (b) adisplacement device for moving the engagement device so that when theengagement device has engaged a magazine, the magazine can be movedbetween a shelf and the support. In one embodiment, the engagementdevice comprises a member with a surface that is used to “hook” amagazine, an actuator for providing the force to move the member intoand out of engagement with a magazine, and a linkage that constrains themember to rotate about an axis. In operation, the engagement device“hooks” a magazine by using the actuator to rotate the member so thatthe “hooking” surface is in position to engage a magazine. To “unhook”the magazine, the actuator is used to rotate the member so the surfaceis no longer in position to “hook” the magazine.

[0014] A further embodiment of the invention provides a method formoving a magazine relative to a shelf in a magazine-based library. Themethod involves displacing the magazine relative to the shelf indiscrete steps that each displace the magazine further towards or awayfrom a shelf. For convenience, the method is initially described withrespect to the moving of a magazine away from a shelf. The methodcomprises providing a device for engaging a magazine and using thedevice to engage the magazine. Once the magazine has been engaged, thedevice is displaced to move the engaged magazine a first distance awayfrom a shelf. After the magazine has been displaced the first distance,the device is disengaged from the magazine and moved back towards theshelf. At this point, the device re-engages the magazine and is thendisplaced away from the shelf to move the re-engaged magazine furtheraway from the shelf. In the case of moving a magazine towards a shelf,the method comprises the steps of providing a device for engaging amagazine and using the device to engage the magazine. Once the magazinehas been engaged, the device is displaced to move the engaged magazine afirst distance towards a shelf. After the magazine has been displacedthe first distance, the device is disengaged from the magazine and movedaway from the shelf. At this point, the device re-engages the magazineand is then displaced towards the shelf to move the re-engaged magazinefurther towards the shelf. The method is capable of being implementedwith an engagement device that “hooks” a magazine. The method is alsocapable of being implemented with an engagement device that is anadaptation of the types of devices that are presently used incartridge-based libraries to grasp cartridges between two members.Typically, the two members in such devices grasp a data cartridge byeither (a) moving one member towards the other member; or (b) movingeach member towards the other member. The movement of a member istypically accomplished by either rotating the member about an axis orlinearly translating the member. In any event, such devices areadaptable to grasping magazines and the method is capable of beingpracticed with devices that are so adapted and any other devices thatare capable of engaging a magazine so that the magazine can bedisplaced.

[0015] A further embodiment of the invention provides a method formoving a magazine relative to a shelf in a magazine-based library. Themethod is initially described with respect to the moving of a magazineaway from a shelf. The method comprises the steps of providing a supportstructure for holding a data cartridge magazine and providing a devicefor engaging a magazine. The method further comprises positioning thesupport structure adjacent to the magazine; causing the device to engagethe magazine; and displacing the device and, as a consequence, theengaged magazine away from the shelf such that at least a portion of themagazine is held by the support structure. The method is capable ofbeing implemented with a device that engages a magazine by “hooking” themagazine. The method is also capable of being implemented with varioustypes of devices for engaging a magazine that, in operation, grasp amagazine between two members, rather than “hook” a magazine. The methodis also practicable with any other device that is capable of engaging amagazine so that the magazine can be displaced.

[0016] Yet a further embodiment of the invention is directed to a methodfor moving magazines between different shelves in a magazine-basedlibrary. The method comprises the steps of providing a device forengaging a magazine and providing a support structure for holding amagazine. The method further comprises positioning the support structureadjacent to a magazine located on a first shelf; causing the device toengage the shelved magazine; and moving the device away from the firstshelf to an extent that the engaged magazine is held by the supportstructure and is no longer held by the first shelf. Further comprisingthe method is the step of moving the device towards a second shelf to anextent that the magazine is supported by the second shelf and no longerassociated with the support structure. In one embodiment, the first andsecond shelves are situated opposite to one another and separated by aspace. In this embodiment, the support structure is used to bridge thespace for the transfer of the magazine from the first shelf to thesecond shelf. The method is capable of being implemented with a devicethat “hooks” a magazine. The method is also capable of being implementedwith the types of devices that operate to grasp a magazine between twomembers, rather than “hook” a magazine. The method is also practicablewith any other device that is capable of engaging a magazine so that themagazine can be displaced.

[0017] A further embodiment of a magazine-based library comprises acartridge transport for moving cartridges to and from a magazine whenthe cartridges are oriented within the magazine and the library suchthat the faces of the cartridges with the greatest surface area lie in asubstantially vertical plane. At least with respect to certain cartridgeform factors and particular or desired library dimensions, it has beendiscovered that the orientation of cartridges in this manner contributesto a high data density footprint. Data density footprint is the amountof data that a library is capable of storing when the maximum number ofdata cartridges that the library is capable of accommodating are housedwithin the library divided by the floor space occupied by the library. Ahigh data density footprint is important in applications where the floorspace that can be dedicated to data storage is limited and the amount ofdata that needs to be stored is relatively large. One notable example ofsuch an application is a data center that provides off-site “backup” or“mirroring” of the data stored on the computer systems of the datacenter's clients. Such data centers typically want to maximize theamount of data that can be stored over a given floor space. In oneembodiment, the cartridge transport comprises a grasper for grasping adata cartridge and a displacement or actuating device for moving thegrasper such that when the grasper is extracting/inserting a cartridgefrom/into a magazine, the cartridge is linearly displaced such that thecartridge moves within a substantially vertical plane. In oneembodiment, the displacement, in addition to being in vertical plane,has a vertical component. In another embodiment, the displacement has ahorizontal or lateral component. In a further embodiment, an additionalactuating device operates to rotate the grasper about a horizontal axisduring the transport of a grasped cartridge from a magazine to a drive.The rotation, in one embodiment, is about a horizontal axis that allowsa grasped data cartridge to be inserted into a drive with a horizontallyoriented slot for receiving a cartridge. In another embodiment, therotation is about a horizontal axis that allows a grasped data cartridgeto be inserted into a drive with a vertically oriented slot forreceiving a data cartridge. The additional actuating device alsooperates to rotate the grasper about a horizontal axis during thetransport of a grasped cartridge from a drive to a magazine.

[0018] Yet another embodiment of a magazine-based library comprises amagazine transport that is capable of moving a magazine, that whenlocated in the library orients a cartridge such that the face of thecartridge with the greatest surface area lies in a vertical plane, to asite at which two or more of the slots of the magazine are accessible bya cartridge transport. The cartridge transport comprises a grasper forgrasping cartridges and a grasper transport that is capable ofhorizontally displacing the grasper such that the grasper can bepositioned adjacent to the two slots of a magazine that has beenpositioned at the noted site by the magazine transport. In oneembodiment, the magazine transport comprises a support for holding amagazine, a magazine engagement device for moving a magazine between thesupport and a shelf, and an elevator for moving the support and magazineengagement device within the library. The grasper and the graspertransport are operatively attached to the elevator and positioned sothat the grasper transport is able to move the grasper to a locationadjacent to one of two or more of the slots of a magazine that is heldby the support so that the grasper can insert/extract a cartridgeinto/from the magazine. In another embodiment, the grasper and graspertransport are not associated with the elevator but rather are fixedlypositioned adjacent to a drive. In this embodiment, the magazinetransport positions a magazine adjacent to the grasper and graspertransport. The grasper transport horizontally moves the grasper to alocation adjacent to one of two or more of the slots of the magazine forinsertion or extraction of a cartridge. In a further embodiment, thecartridge transport comprises an additional actuating device orstructure that is used to linearly displace a cartridge relative to themagazine during extraction of a cartridge from the magazine andinsertion of a cartridge into the magazine. In yet a further embodiment,an additional actuating mechanism is employed to rotate the grasperabout a horizontal axis to facilitate the transport of a cartridgebetween the drive and a magazine.

[0019] Another embodiment of a magazine-based library comprises amagazine transport for moving a magazine within the library, a cartridgetransport for moving a cartridge between a magazine and a drive, and anelevator that is part of both the magazine transport and the cartridgetransport. In one embodiment, the elevator comprises a carriage to whichboth a magazine picker and a grasper are attached, and a surface forholding a magazine. Such a magazine-based library is capable of a “bulkload” operation in which: (a) the magazine picker moves a magazine froma shelf onto the support; (b) the elevator moves the support andassociated magazine to a location adjacent the drives; and (c) thegrasper is then used to repeatedly move a cartridge from the magazineinto one of the drives until the desired number of cartridges have beenloaded. In one embodiment, the cartridge transport comprises a grasperfor grasping the cartridges and a grasper transport for moving thegrasper such that the grasper can be positioned adjacent to at least twoof the slots of a magazine when the magazine is associated with thesupport. In a particular embodiment, the grasper transport is capable ofpositioning the grasper adjacent to each slot of a magazine that isappropriately positioned on the support.

[0020] Yet a further embodiment of a magazine-based library comprises adevice for reading a label that is associated with a magazine, as wellas labels that are associated with any cartridges held by the magazine.In “cartridge-based” libraries there is a need to be able to identifycartridges within the library because a particular cartridge will notnecessarily be permanently associated with a particular storage slot.The cartridge picker in such libraries can move the cartridge from onestorage slot to another storage slot, to an entry/exit port, or toanother library via a pass-through port. Consequently, to be able todetermine which a cartridge is in a particular location within alibrary, the cartridges need to be susceptible to identification.Presently, identification of cartridges is accomplished by associating abar-code label with each cartridge in the library and positioning thebar-code label such that a bar-code reader is readily able to read thebar-code associated with the cartridge. However, there is no need in“cartridge-based” libraries that employ magazines to create cartridgestorage slots to be able to identify a magazine within the librarybecause such libraries do not manipulate or move magazines within thelibrary during operation. Consequently, the magazines that are used incartridge-based libraries do not bear labels that identify the magazineand that can be read by any kind of label reader located within thelibrary. However, in a magazine-based library, because the location of amagazine is not fixed and can be changed using a magazine transporter,there is a need to be able to identify each magazine. In one embodiment,the device for reading the magazine label and cartridge labels comprisesa label reader (e.g., a bar code reader) and an actuating device formoving the label reader between a first orientation at which the readeris capable of reading a magazine label and a second orientation at whichthe reader is able to read cartridge labels. In one embodiment, thelabel reader is associated with the element of the cartridge transportthat grasps data cartridges. In another embodiment, the device iscomprised of two label readers, one label reader for reading a magazinelabel and a second reader for reading cartridge labels. In oneembodiment that employs two label readers, the first reader isassociated with the element of the cartridge transport that grasps datacartridges, and the second reader is associated with a magazine pickerthat moves magazines to and from shelves in the library.

[0021] Another embodiment of a magazine-based library comprises acartridge transport that is capable of accommodating cartridges ofdifferent dimensions. The particular dimensions associated with a datacartridge are commonly referred to as a form factor. For tape datacartridges, common form factors include DLT (digital linear tape), LTO(linear tape open), and SAIT (super advanced intelligent tape). Thepresent invention provides a magazine-based library with a cartridgetransport that is able to grasp cartridges that conform to two differentform factors. To elaborate, the cartridge transport comprises a housingthat serves to constrain a cartridge in at least one dimension. Thehousing is capable of adapting to cartridges that have differentmeasurements in one dimension, such as the height dimension. In oneembodiment, the housing comprises a first planar surface and a secondplanar surface that is substantially parallel to and separated from thefirst planar surface. Further, the first planar member is able to moverelative to the second planar member so that the distance between thetwo members can be adjusted to accommodate the differences in thedistances between two substantially parallel surfaces associated withtwo cartridges that each conform to a different form factor. In oneembodiment, the planar members are able to accommodate LTO and DLT tapecartridges, which have different heights (height being the distancebetween the two substantially parallel faces of the cartridge that havethe greatest surface area).

[0022] Another embodiment of a magazine-based library comprises anentry/exit port for conveying a magazine between: (a) a space that isinterior to the library and accessible by a magazine transport devicethat can place a magazine in the port or remove a magazine from theport; and (b) an exterior environment where an operator can place amagazine in the port or remove a magazine from the port. It should beappreciated that such an entry/exit port is markedly different than theentry/export ports in “cartridge-based” libraries that utilize amagazine to move cartridges into and out of a library. In acartridge-based library that employs an entry/exit port, the cartridgepicker cannot move the magazine, the cartridge picker can only moveindividual cartridges between the magazine associated with the port andother locations in the library. In contrast, the entry/exit port of a“magazine-based” library allows a magazine picker to move magazines intoand out of the port.

[0023] In one embodiment, the entry/exit port comprises a tray forsupporting a magazine and selectively holding the magazine in asubstantially fixed position relative to the tray during the movement ofa magazine between the exterior environment and the space that isinterior to the cabinet. The ability to selectively hold the magazine ina fixed position is particularly important during the transport of amagazine between the exterior environment and the interior space that isaccessible by the magazine picker. To elaborate, momentum is imparted tothe magazine during transport of the magazine between the exteriorenvironment and the interior space. If the magazine was not fixed inplace during the transport, the momentum could possibly carry themagazine into the interior of the library in a manner that couldadversely affect the operation of the library. In one embodiment, thetray comprises a fixed wall and a spring-loaded, opposing wall that arecapable of clamping a magazine in place during transport. When the trayis positioned so that the magazine picker can access the tray, thespring-loaded, opposing wall is retracted to unclamp any magazine beingsupported by the tray so that the magazine picker can remove themagazine from the tray.

[0024] A further embodiment of the entry/exit port comprises a doorsystem that prevents an operator from accessing the interior of thelibrary via the entry/exit port. In one embodiment, the entry/exit portcomprises an exterior door and an interior door that operate such thatduring the time that the exterior door is opening to allow an operatorto access the port, the interior door is closing to prevent the operatorfrom accessing the interior of the library via the port and frompossibly being injured by moving elements within the library.Conversely, during the time that the exterior door is closing, theinterior door is opening to allow the magazine picker to access theport. In one embodiment, a linkage between the interior and exteriordoors is employed to achieve the coordinated operation.

[0025] A further embodiment employs a tray for supporting a magazinethat moves between a position that is exterior to the library so that anoperator can access the tray and a position that is interior to thelibrary so that a magazine picker can access the tray. In thisembodiment, a linkage is employed that coordinates the opening andclosing of the doors with the movement of the tray. To elaborate, thelinkage operates such that during the time that the tray is moving fromthe position that is exterior to the library to the position that isinterior to the library, the exterior door moves from the open positiontowards the closed position and the interior door moves from the closedposition towards the open position. Conversely, during the time that thetray is moving from the position that is interior to the library to theposition that is exterior to the library, the exterior door moves fromthe closed position towards the open position and the interior doormoves from the open position towards the closed position. In oneembodiment, the interior and exterior doors are substantially planar andare operated in a “drawbridge” fashion such that each of the doorsrotate about an axis that is substantially parallel to the face of thedoor. Other door structures are feasible, including a door structurethat rotates about a different axis to move between open and closedpositions, a door structure that is linearly translated between open andclosed positions, and a multi-element door. In a further embodiment, asingle actuator is used to achieve the movement of the tray and theinterior and exterior doors. Yet another embodiment of the entry/exitport employs a carousel with a body that holds a magazine and thatrotates about an axis. The body serves to prevent an operator fromaccessing the interior of the library. Consequently, the carouselapproach avoids the use of doors. However, the implementation of acarousel entry/exit port is likely to reduce the space available formagazines and/or drives in the library.

[0026] Also provided is a magazine that is suitable for use in amagazine-based library in which magazines are moved within the library.The magazine is comprised of: (a) a frame that defines a space foraccommodating a plurality of data cartridges; (b) a partitioningstructure for dividing the space into a plurality of slots with eachslot being capable of accommodating a data cartridge and supporting thecartridge such that when the magazine is associated with themagazine-based library, the face of the cartridge with the greatestsurface area lies in a vertical plane; and (c) an engagement structurethat allows the magazine to be engaged by a magazine picker for movementwithin the library. In one embodiment, the engagement structurecomprises a hole for use in magazine-based libraries that employ amagazine picker that utilizes a member to “hook” magazines. Anotherembodiment employs an engagement structure that is adapted for use witha magazine picker that utilizes two members to grasp a magazine. In oneembodiment, the engagement structure comprises a pair of holes. Inanother embodiment, the engagement structure comprises a pair ofprotrusions that extend beyond a surface or surfaces of the frame. Yet afurther embodiment comprises a pair of indentations in a surface orsurfaces of the frame. Yet a further embodiment of the magazinecomprises a flag structure for use in determining when a magazine pickerhas engaged the magazine. In one embodiment, the flag structurecomprises an element that blocks an optical signal when the magazinepicker has engaged the magazine.

[0027] Another embodiment of the magazine comprises a “label” structurefor use in identifying the magazine within the library so that, forexample, the location of the magazine in the library can be tracked.There is no need in a “cartridge-based” library that employs magazinesto create fixed storage slots to identify the magazines during theoperation of the library because the library does not manipulate or movemagazines within the library during operation. As previously noted,magazines in cartridge-based libraries primarily serve to make it easierfor an operator to hand load/unload a large number of cartridgesinto/from the library. In contrast, in a magazine-based library,magazines are manipulated during operation of the library and, as aconsequence, there is a need to be able to identify a magazine within alibrary. In one embodiment, the label structure comprises an indentationin a surface of the magazine that is capable of accommodating anadhesive label, such as an adhesive bar-code label. Another embodimentcomprises a receptacle that is associated with the magazine and that iscapable of receiving a label or other identifier, such as a radiofrequency identification RFID tag. In yet another embodiment, anidentifier, such as an RFID tag, is embedded within the magazine.Identifiers with fixed or programmable identification information arealso feasible.

[0028] Another embodiment of the magazine comprises a structure forinhibiting, when the magazine is on a shelf within a magazine-basedlibrary, movement of the magazine other than movement attributable tothe magazine picker. In one embodiment, the structure comprises a detentthat cooperates with a notch associated with a shelf to hold themagazine in a desired location on a shelf. The engagement between thenotch and the detent serves to resist forces that might displace themagazine. The resistance provided by this engagement is not, however,great enough so that it cannot be overcome by a magazine picker. Afurther embodiment of the structure comprises one portion of an activelatching mechanism, the other portion of the latching mechanism beingassociated with the shelf. In one active latch embodiment, the structureassociated with the magazine comprises a receptacle that is designed toengage an active element associated with the shelf. In another activelatch embodiment, the structure associated with the magazine comprisesan active element that is adapted to engage a receptacle associated witha shelf. One such active element comprises a cantilevered detent. Inoperation, the cantilever provides a spring force that must be overcometo disengage the detent from the receptacle and, as a consequence,resists forces that might displace the magazine from a preferredlocation.

[0029] A further embodiment of a magazine-based library comprises adrive bay for holding a drive in an operative position within thelibrary and facilitating relatively speedy insertions and extractions ofthe drive. Most drives have a front face with a slot for receiving adata cartridge and rear face with one or more plugs for receiving power,control signals, and data signals. In many cartridge-based libraries,when such a drive is operatively situated in a library, the front faceof the drive is accessible to the cartridge picker. The drive is alsotypically situated near a removable panel or door of the library housingso that an operator can readily access the drive. Further, the drive istypically attached to a frame to prevent the drive from moving duringoperation of the library. To remove or replace such a drive, theoperator has to remove the panel or open the door to obtain access tothe drive, disconnect the drive from all of the electrical connectorsthat are providing power, control signals, and data signals to thedrive, and then unfasten the drive from the frame. In many situations,the library is powered down during such an operation. The magazine-basedlibrary with a drive bay substantially reduces the work and, hence, thetime required for such operations. To elaborate, in one embodiment, thedrive bay comprises a housing with two open sides, where one of the opensides is exposed to the cartridge transport and the other open side isexposed to an environment that is accessible to an operator so that theoperator can insert or extract a drive from the housing. Furthercomprising the drive bay is a sled that is capable of holding a drive.The sled comprises an electrical connector with one or more drive plugsthat mate with the plug(s) on the rear face of the drive, one or moresled plugs, and one or more electrical conductors extending between thedrive plug(s) and the sled plug(s). The sled plug(s) is/are oriented soas to face towards the first open side of the housing, i.e., towards thecartridge transport. The drive bay further comprises housing plug(s)that face the second opening or the area accessible to the operator. Thehousing plug(s) is/are positioned in the housing so that when anoperator inserts the sled into the housing with the proper orientation(i.e., such that if the sled held a drive, the front face of the drivewould be accessible to the cartridge transport), the sled plug(s) engagethe housing plug(s). As a consequence, the insertion of a drive into thelibrary is accomplished by pushing a sled with the drive into thehousing such that the sled plug(s) and the housing plug(s) engage oneanother. Conversely, removal of a drive from the library is accomplishedby extracting the sled and drive form the housing, which causes the sledplug(s) and housing plug(s) to disengage from one another. Consequently,the drive bay eliminates the need for an operator to spend timedisconnecting/connecting cables from plug(s) associated with the rearface of the drive during the extraction/insertion of a drive. Further,since the drive is attached to the sled and not a fixed frame within thelibrary, the drive bay eliminates the need to spend timedetaching/attaching a drive from/to such a frame. In one embodiment, thedrive bay housing is comprised of multiple sub-bays with each sub-baycapable of accommodating a sled and having a housing plug forestablishing an electrical connection with a sled residing in thesub-bay.

[0030] In yet another embodiment, a magazine-based library comprises anoperator alterable space within the housing, i.e., a space whosefunction in the library is subject to a choice by an operator. Thealterable space is capable of accommodating at least two different typesof library modules. Among the possible types of modules are shelvingmodules and drive modules. The alterable space is defined by a firstopen side that is accessible to the cartridge transport and/or magazinepicker and a second side that is accessible to an operator. Associatedwith the alterable space is a mounting structure that allows a module tobe readily mounted within the library or de-mounted from the library.Among the possible modules is a drive bay module that, in addition tothe features of a drive bay described above, also has a drive baymounting structure that cooperates with the library mounting structureto facilitate securing the module within the library and removing themodule from the library. Another module is a magazine bay module thatprovides one or more shelves, each for holding at least one magazine.The magazine bay module has a magazine bay mounting structure thatcooperates with the library mounting structure to facilitate securingthe magazine bay within the library and removing the module from thelibrary.

[0031] A further embodiment of a magazine-based library comprises apower system that is used to provide power to the drive(s) within thelibrary and that allows the space within the library to be utilized moreefficiently. In many cases, the power system allows more data cartridgesto be housed within a library relative to a library that employs atypical power system. This advantage is particularly discernable inlibraries that employ multiple drives. To elaborate, most data cartridgelibraries include one or more power supplies for providing power to thedrive or drives within the library. In libraries that employ multipledrives, power is typically conveyed from the power supply or suppliesvia multiple cables, each with a circular cross-section and each with aconductor surrounded by an insulating cover. Typically, these cables arebundled together. This bundle of cables typically has a cross-sectionthat is roughly circular. The cross-sectional shape of the bundle makesit awkward to “fit” the bundle with other elements of the library toefficiently utilize the space within the library. The embodiment of themagazine-based library comprises a power supply and a conductorstructure for distributing power produced by the power supply to thedrive(s) in the library that is flat, i.e., has two external and flatsurfaces that are separated from one another and substantially parallelto one another. For the distribution of power to a given number ofdrives, the distance between the flat external surfaces is less than thediameter of a bundle of circular conductors. This reduced dimensiontypically allows the space within the library to be more efficientlyused and, in many cases, allows a greater number of data cartridges tobe stored within the library. Further, the flat shape of the conductorlends itself to being integrated with the other components of thelibrary, many of which are box-shaped, so that the space within thelibrary can be more efficiently used relative to libraries that employpower conductors with circular cross-sections and bundles of suchconductors.

[0032] Further, the insulating covers associated with the conductors ina bundle of cables may provide more insulation than is needed toelectrically insulate the conductors from one another. Consequently,insulating covers occupy more space over a diameter of the cross-sectionof the bundle than is needed. In one embodiment, the conductor iscomprised of a plurality of laminated electrical conductors that areseparated from one another by insulating material. In a transit betweenthe two external flat surfaces, the amount of space dedicated toinsulating material is less than that for a comparable bundle of cables.Consequently, relative to a bundle of cables, the conductor structureprovides additional space for other uses.

[0033] Yet another embodiment of the invention is directed to a methodthat allows a user to upwardly scale or expand the size of amagazine-based library in a modular manner. The method comprises thestep of providing a magazine-based library with a cabinet surface thatis alterable to form a passageway through the cabinet so that thelibrary can be joined to an add-on module and magazines can betransferred between the library and the add-on module. Themagazine-based library further comprises an elevator structure that isused to horizontally displace a magazine picker that is capable ofmoving magazines to and from the shelves in the library. The methodfurther comprises the step of providing an add-on module with a sidesurface that is either alterable to form a passageway or already has apassageway. The add-on cabinet can take a number of forms. For example,the add-on module may be able to accommodate a shelf, multiple shelves,a drive, multiple drives, combinations of the foregoing elements, or bea self-sufficient magazine-based library. In one embodiment, the methodfurther comprises replacing whatever portion (s) of the elevatorstructure in the library serves to limit the horizontal range over whichthe magazine picker can be moved within the library with a longerstructure that extends through the passageways of the library and theadd-on. In another embodiment, the method comprises the further step ofproviding an add-on to the existing elevator structure such that anelevator is modularly expanded and the resulting expanded elevator iscapable of transporting the magazine picker through the passageways ofthe library and the add-on. In yet a further embodiment, the add-on hasits own magazine transport device and the two magazine transport devices(one associated with the library and the other associated with theadd-on) are capable of directly passing a magazine from one to theother. In yet another embodiment, the add-on comprises a separatemagazine transport device from that of the library. However, the twomagazine transports are incapable of directly passing a magazine fromone to another. Consequently, the method comprises the further step ofproviding a third magazine transport device that serves as anintermediary transport device between the transport device associatedwith the library and the transport device associated with the add-on.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034]FIG. 1 is a block diagram of a magazine-based data cartridgelibrary that illustrates necessary and optional features of the library;

[0035]FIGS. 2A-2E are plan views of five rectilinear layouts for amagazine-based data cartridge library;

[0036]FIGS. 3A-3G are plan views of seven cylindrical layouts for amagazine-based data cartridge library;

[0037]FIGS. 4A and 4B are plan view of two moving shelf layouts for amagazine-based library;

[0038]FIGS. 5A-5C are a perspective view of a drive, a front view of thedrive in a vertical orientation, and a front view of the drive in ahorizontal orientation;

[0039]FIGS. 6A-6C are perspective views of the exterior of an embodimentof a magazine-based data cartridge library (hereinafter library);

[0040]FIG. 7A is a perspective view of the embodiment of the libraryshown in FIGS. 6A-6C with the various elements, such as certain cabinetsurfaces removed, and the library populated with magazines;

[0041]FIG. 7B is a perspective view of the embodiment of the libraryshown in FIGS. 6A-6C with certain elements removed, including all butone drive bay, and populated with a few magazines;

[0042]FIG. 8A is a perspective sectional interior view of the librarywith certain features removed, such as the entry/exit port, and theshelves in the view fully populated with magazines;

[0043]FIG. 8B is a perspective-sectional interior view of the librarythat is fully populated with drives and the shelves in the fullypopulated with magazines;

[0044]FIGS. 9A-9B illustrate an LTO tape cartridge;

[0045]FIGS. 10A-10B illustrate a SAIT tape cartridge;

[0046]FIGS. 11A-11B illustrate a DLT tape cartridge;

[0047]FIGS. 12A-12D illustrate an embodiment of a magazine that iscapable of accommodating both LTO and SAIT tape cartridges;

[0048]FIGS. 13A-13B are cross-sectional views of the magazine shown inFIGS. 12A-12D that respectively show an LTO tape cartridge and a SAITtape cartridge within the magazine;

[0049]FIGS. 14A-14B illustrate an embodiment of a magazine that iscapable of accommodating a DLT tape cartridge;

[0050]FIG. 15 is a cross-sectional view of the magazine shown in FIGS.14A-14B that shows a DLT tape cartridge within the magazine;

[0051]FIG. 16 is a schematic plan view of the general layout of thelibrary;

[0052]FIGS. 17A-17B respectively are a front perspective view of anembodiment of a dual entry/exit port and a rear view of the dualentry/exit port;

[0053]FIGS. 18A-18F illustrate various elements of one port of the dualentry/exit port;

[0054]FIGS. 19A-19E illustrate the operation of the port shown in FIGS.18A-18E in moving a magazine from an exterior environment to a space inwhich the magazine is accessible by a magazine transport device;

[0055]FIGS. 20A-20E illustrate examples of alternative door structuresfor an entry/exit port;

[0056]FIGS. 21A-21B illustrate a carousel entry/exit port;

[0057]FIGS. 22A-22C respectively illustrate an embodiment of a shelfcapable of holding five magazines, an embodiment of a cleat that isassociated with the shelf, and the relationship between the shelf andmagazine;

[0058]FIGS. 23A-23C are respectively a front perspective view of anembodiment of a four unit, drive bay assembly populated with fourdrives, a rear perspective of the drive bay assembly, and a rear view ofan embodiment of a ladder frame that is used to hold the drive bayassembly in the library;

[0059]FIGS. 24A-24F illustrate features of the housing portion of thedrive bay assembly;

[0060]FIG. 25 illustrates the plug interface of a typical drive;

[0061]FIGS. 26A-26C illustrate the sled portion of the drive bayassembly;

[0062]FIGS. 27A-27E illustrate an embodiment of a power supply systemthat utilizes a flat power conductor to provide DC power to the drivesin the library;

[0063]FIGS. 28A-28B illustrate an embodiment of a magazine bay assembly;

[0064]FIGS. 29A-29H illustrate features of an embodiment of an elevatorthat is used to move a magazine picker;

[0065]FIGS. 30A-30G illustrate an embodiment of a magazine picker;

[0066]FIGS. 31A-31L are cross-sectional and free body diagrams thatillustrate the operation of the magazine picker in moving a magazinefrom one shelf to another shelf;

[0067]FIG. 32 illustrates an alternative magazine engagement device;

[0068]FIGS. 33A-33N illustrate an embodiment of a cartridge transport;

[0069]FIGS. 34A and 34B respectively illustrate the range of motion ofthe housing of the cartridge transport and the ability of a bar codereader to read a bar code label that identifies a magazine and a barcode label that identifies a cartridge;

[0070]FIGS. 35A-35C illustrate steps associated with moving a datacartridge between a magazine and a drive;

[0071]FIGS. 36A-36G are free body diagrams that illustrate an embodimentof a cartridge transport unit extracting/inserting a data cartridgefrom/into magazine;

[0072]FIGS. 37A-37G are free body diagrams that illustrate an embodimentof a cartridge transport unit inserting/extracting a data cartridgeinto/from drive;

[0073]FIG. 38 illustrates the relationship between the space occupied bymagazines resident in the library and the space utilized by the magazinetransport and cartridge transport in the library;

[0074]FIG. 39 illustrates the controller and the relationship of thecontroller to the electrical elements in the library and the powerdistribution system;

[0075]FIGS. 40A-40F illustrate alternative embodiments of magazines thatoperatively orients cartridges within a magazine-based data cartridgelibrary such that the face of the cartridge with the greatest surfacearea lies in a vertical plane;

[0076]FIGS. 41A-41B illustrate an alternative embodiment of a magazinethat operatively orients cartridges within a magazine-based datacartridge library such that the face of the cartridge with the greatestsurface area lies in a vertical plane;

[0077]FIG. 42 illustrates an alternative embodiment of a magazine thatis operative with the library;

[0078]FIGS. 43A and 43B respectively illustrate an expanded library anda schematic representation of the process for producing the expandedlibrary;

[0079]FIGS. 44A-44B schematically illustrate alternative methods ofproducing an expanded library; and

[0080]FIGS. 45A-45E illustrate various embodiments of magazinepass-through ports for passing magazines between magazine-basedlibraries.

DETAILED DESCRIPTION

[0081] The present invention is directed to a magazine-based datacartridge library that is capable of moving data cartridge magazineswithin the library, as well as moving individual cartridges within thelibrary.

[0082] With reference to FIG. 1, the present invention is directed to amagazine-based data cartridge library 100 comprised of: (a) a frame 102for supporting the other elements of the library; (b) a shelving system104 for supporting at least two data cartridge magazines; (c) one ormore drives 106 that are each capable of writing and/or reading datato/from a recording medium in a data cartridge; (d) a magazine transport108 for moving a magazine within the library; (e) a cartridge transport110 for moving a data cartridge between a magazine and a drive; and (f)an interface 112 for communicating with a host computer that uses thelibrary to store data.

[0083] As noted, the frame 102 provides a support for the other elementsof the library. In addition, the frame may comprise one or more exteriorsurfaces that form a cabinet for enclosing most of the components of thelibrary. Typically, the cabinet establishes an environment whosetemperature can be controlled for the benefit of the elements of thelibrary housed within the cabinet. The cabinet also commonly serves as abarrier to contaminates that could adversely affect the operation of theelements of the library housed within the library. Additionally, thecabinet is also useful in preventing an individual from accessing thespace within the cabinet during operation of the library and potentiallybeing injured by the moving elements within the library.

[0084] There are a number of devices that do not necessarily need to bepart of the magazine-based-data cartridge library 100 (i.e., notsupported by the frame) but are nonetheless needed for the library tofunction and, as a consequence, typically are part of the library. Amongthese devices are a power supply system 114 (which may be comprised ofmultiple power supplies) and a controller 116 for managing theoperations of the library. If the magazine-based data cartridge library100 is unable to passively dissipate enough heat for the elements of thelibrary to function, environmental devices 118 (e.g., fan, fins, heatpipes etc.) are also incorporated into the library.

[0085] In addition, there are several devices that typically are notrequired for the magazine-based library 100 to function as amagazine-based library but are nonetheless desirable in certainembodiments. Among these devices are an entry/exit port 120 for moving amagazine between an exterior environment that is accessible to anoperator and a space that is accessible by the magazine transport; apass-through port 122 for moving magazines between magazine-based datacartridge libraries; and an operator interface 124 that allows anoperator to interact with the library.

[0086] There are several possible layouts for the magazine-basedcartridge library 100. Many of these layouts can be characterized ortyped as rectilinear or circular/cylindrical. In a rectilinear type,magazine-based data cartridge library, at least the drive or drive andthe shelf or shelves of the shelf system are laid out along: (a) astraight line or plane; or (b) along multiple straight lines or planesthat are parallel and/or perpendicular to one another. Morespecifically, in a rectilinear type library, the face of a drive thathas a receptacle for receiving a data cartridge is oriented such thatthe direction that a data cartridge is displaced when the cartridge iseither inserted or extracted from the receptacle by the cartridgetransport is substantially perpendicular to a straight line or plane.Similarly, a shelf in a rectilinear type library is oriented such thatthe direction that a magazine is displaced when the magazine is eitherassociated with a shelf or removed from a shelf by the magazinetransport is substantially perpendicular to a straight line or plane.Typically, most of the other elements of the library are also laid outin the same manner.

[0087]FIGS. 2A-2E are plan views of five different rectilinear typelayouts for the magazine-based data cartridge library 100. In the layoutillustrated in FIG. 2A, a drive 128 (or drives) and/or a shelf 130 (orshelves) are oriented along a straight line/plane 132. A robot 134 isprovided that cumulatively represents the magazine transport 108 and thecartridge transport 110. With respect to the rectilinear type layoutsshown in FIGS. 2B-2E, the drive and shelf elements retain the samereference numbers as those elements bear in FIG. 2A. In the embodimentillustrated in FIG. 2B, at least one drive 128 and/or at least one shelf130 is/are laid out along line/plane 136A, and at least one drive 128and/or at least one shelf 130 is/are laid out along line/plane 136B,which is parallel to line/plane 136A. In the embodiment illustrated inFIG. 2C, at least one drive 128 and/or at least one shelf 130 is/arelaid out along line/plane 138A, and at least one drive 128 and/or atleast one shelf 130 is/are laid out along line/plane 138B, which isperpendicular to line/plane 138A. With respect to the embodiment of FIG.2D, at least one drive 128 and/or at least one shelf 130 is/are laid outalong each of lines/planes 140A, 140B and 140C, with lines/planes 140Aand 140B being parallel to each other and perpendicular to line/plane140C. In the embodiment illustrated in FIG. 2E, at least one drive 128and/or at least one shelf 130 is/are laid out along each of lines/planes142A-142D, with lines/planes 142A, 142B being parallel to one another,and with lines/planes 142C, 142D being parallel to one another andperpendicular to the parallel lines/planes 142A, 142B. It should beappreciated that each of the embodiments comprises at least one drive.Further, each embodiment comprises at least one shelf that is capable ofsupporting two or more magazines or multiple shelves that cumulativelysupport two or more magazines. It should also be appreciated that theillustrated location of a drive or shelf along a line/plane is merelyillustrative and that the actual location of a drive or shelf can beanywhere along a line/plane. It should also be appreciated that, whilethe robot 134 cumulatively represents the magazine transport 108 andcartridge transport 110, the magazine transport 108 and the cartridge110 may share one or more elements or be entirely separate from oneanother. It should be further appreciated that there may be otherrectilinear layouts for the magazine-based data cartridge library 100and characteristic of each such layout is a magazine transport.

[0088] In a circular/cylindrical type, magazine-based data cartridgelibrary, the drive or drives and shelf or shelves of the shelf systemare laid out along radial lines that have a common center and/or alongone circular arc or multiple, concentric circular arcs. Morespecifically, in a circular type library, the face of a drive that has areceptacle for receiving a cartridge is oriented such that the directionthat a data cartridge is displaced when the cartridge is either insertedor extracted from the receptacle is either: (a) substantially along aradial line/plane, (b) substantially along a line/plane that is parallelto a radial line/plane, or (c) along a line that is tangent to acircular arc. Similarly, a shelf in a circular type library is orientedsuch that the direction that a magazine displaced when the magazine iseither associated with a shelf or removed from a shelf by the magazinetransport is either: (a) substantially along a radial line/plane, (b)substantially along a line/plane that is parallel to a radialline/plane, or (b) along a line that is tangent to a circular arc.

[0089]FIGS. 3A-3G are plan views of seven different circular/cylindricaltype layouts for the magazine-based data cartridge library 100. In thelayout illustrated in FIG. 3A, a drive 146 (or drives) and/or shelf 148(or shelves) are respectively oriented along radial lines 150A, 150Bthat have a common center 152 and along a circular/cylindrical arc 153.A robot 154 is provided that cumulatively represents the magazinetransport 108 and the cartridge transport 110. With respect to thecircular/cylindrical type layouts shown in FIGS. 3B-3G, the term drive146 refers to one or multiple drives and the term shelf 148 refers toone or more shelves. Additionally, reference numbers for elements commonto the various embodiments have been retained as a matter ofconvenience. In the embodiment illustrated in FIG. 3B, at least onedrive 146 and/or at least one shelf 148 is/are laid out along a radialline(s) and along a first circular/cylindrical arc 156A, and at leastone drive 146 and/or at least one shelf 148 is/are laid out along aradial line(s) and along a second circular/cylindrical arc 156B that isconcentric to the circular arc 156A. The robot 154 moves in a space thatis located between the two concentric arcs 156A, 156B. It should beappreciated that the embodiments illustrated in FIGS. 3A and 3B are eachcapable of being implemented such that the shelf or shelves and drive ordrives are laid out along a circular/cylindrical arc that defines acomplete or substantially complete circle or cylinder. In the embodimentillustrated in FIG. 3C, at least one drive 146 and/or at least one shelf148 is/are laid out along a radial line(s) and along acircular/cylindrical arc 156A, and at least one drive 146 and/or atleast one shelf 148 is/are laid out along a tangent line 158 to acircular/cylindrical arc 160 that typically represents the path traveledby an element of the robot 154. The embodiment illustrated in FIG. 3D isa combination of the characteristics or features noted with respect tothe embodiments shown in FIGS. 3B and 3C. In the embodiment illustratedin FIG. 3E, at least one drive 146 and/or at least one shelf 148 is/arelaid out along a tangent line 162A to the circular/cylindrical arc 160,and at least one drive 146 and/or at least one shelf 148 is laid outalong a tangent line 162B to the circular/cylindrical arc 160. Theembodiment illustrated in FIG. 3F is a combination of thecharacteristics or features noted with respect to the embodiment shownin FIGS. 3B and 3E. In the embodiment illustrated in FIG. 3G, at leastone drive 146 and at least one shelf 148 is/are laid out along thetangent line 158 of the circular/cylindrical arc 160. In yet a furtherembodiment (not shown), at least one drive and/or a least one shelf arelocated along each of two or more circular arcs with a common center andan element of the robot 154 is cable of moving between the arcs. Itshould be appreciated that each of the embodiments comprises at leastone drive. Further, each embodiment comprises at least one shelf that iscapable of supporting two or more magazines or multiple shelves thatcumulatively support two or more magazines. It should also beappreciated that the illustrated location of a drive or shelf along acircular/cylindrical arc is merely illustrative and that the actuallocation of a drive or shelf can be anywhere along thecircular/cylindrical arc. It should also be appreciated that, while therobot 154 cumulatively represents the magazine transport 108 andcartridge transport 110, the magazine transport 108 and the cartridgetransport 110 may share one or more elements or be entirely separatefrom one another. It should be further appreciated that there may beother circular layouts for the magazine-based data cartridge library 100and characteristic of each such layout is a magazine transport.

[0090] Yet another possible layout for the magazine-based data cartridgelibrary 100 is a movable-shelf type in which at least two shelves aremoveable to facilitate the positioning of the shelves relative to themagazine transport. FIG. 4A is a plan view of one embodiment of amovable-shelf layout for the magazine-based data cartridge library 100.The embodiment comprises a rotating shelf structure 166 with shelves168A-D, a robot 170 that cumulatively represents the magazine transport108 and cartridge transport 110, and one or more stationary drives 172.In operation, the shelf structure 166 is rotated to place one of theshelves 168A-D in the same plane as the robot 170 so that the robot 170can perform a magazine or cartridge operation. In an alternativeembodiment, one or more drives are also associated with the rotatingshelf structure 166. FIG. 4B is a plan view of another embodiment of amovable-shelf layout for the magazine-based library 100 that includesmovable drives. Elements common to this embodiment and the embodiment inFIG. 4A have been given the same reference numbers. The embodiment shownin FIG. 4B comprises the further element of a rotating drive structure174 that is capable of holding multiple drives 176A-D and positioningeach of the drives for the transfer of a data cartridge with the robot170. In other embodiments, one or more drives are associated with therotating shelf structure 166 and/or one or more shelves are associatedwith the rotating drive structure 174. Although not illustrated anotherpossible layout for the magazine-based data cartridge library ismovable-drive type that is comprised of a stationary shelf system andmovable drives. In essence, the rotating drive structure 174 of theembodiment illustrated in FIG. 4B in combination with a stationary shelfsystem. It should be appreciated that each of the embodiments comprisesat least one drive. Further, each embodiment comprises at least oneshelf that is capable of supporting two or more magazines or multipleshelves cumulatively support two or more magazines. Moreover, while theillustrate embodiments contemplate that the rotating elements rotateabout a vertical axis, rotation about a horizontal axis is alsofeasible. It should also be appreciated that, while the robot 134cumulatively represents the magazine transport 108 and cartridgetransport 110, the magazine transport 108 and the cartridge transport110 may share one or more elements or be entirely separate from oneanother. It should be further appreciated that there may be othermovable-shelf layouts for the magazine-based data cartridge library 100and characteristic of each such layout is a magazine transport.

[0091] The magazine-based data cartridge library 100 is also capable ofbeing implemented in a layout that is a combination of two or more ofthe rectilinear type, circular type, movable-shelf type, andmovable-drive type layouts. Further, characteristic of each such layoutis a magazine transport.

[0092]FIG. 5A illustrates a typical drive 180 that is employed in themagazine-based data cartridge library 100. The drive 180 is capable ofwriting data to and/or reading data from a recording medium that islocated within a cartridge. Typically, the drive is capable of bothwriting data to and reading data from a recording medium located in alibrary. The drive 180 is comprised of a housing 182 with a frontsurface 184 that has a receptacle 186 for receiving a cartridge. Thehousing 182 further comprises a back surface (not shown) and sidesurface 188 that is comprised of a first surface 190A, a second surface(not shown) that is substantially parallel to the first surface, a thirdsurface 190B that is substantially perpendicular to the first surface190, and a fourth surface (not shown) that is substantially parallel tothe third surface 192. Typically, the drive 180 is situated in thelibrary 100 such that the first surface 190A lies in a horizontal planeor in a vertical plane. When the receptacle 186 is longer in onedimension than the other and extends in a direction that issubstantially parallel to the first surface 190A, these orientationsresult in the long dimension of the receptacle 186 extending eitherhorizontally or vertically. FIG. 5B illustrates the drive 180 with anorientation in which the long dimension of the receptacle 186 extendshorizontally. In a circular/cylindrical type implementation, either ahorizontal receptacle center line 192 or a horizontal drive center line194 of the drive 180 is typically located: (a) substantially along aradial line/plane, (b) substantially along a line/plane that is parallelto a radial line/plane, or (b) along a line that is tangent to acircular arc. FIG. 5C illustrates the drive 180 in an orientation inwhich the long dimension of the receptacle 186 extends vertically. In acircular/cylindrical type implementation, either a vertical receptaclecenter line 196 or a vertical drive center line 198 of the drive 180 istypically located: (a) substantially along a radial line/plane, (b)substantially along a line/plane that is parallel to a radialline/plane, or (b) along a line that is tangent to a circular arc.

[0093] It should be appreciated that the magazine-based data cartridgelibrary 100 is capable of being adapted to any type of drive that iscapable of writing date to and/or reading data from a recording mediumlocated in a cartridge. Concomitantly, the magazine-based data cartridgelibrary 100 is also adaptable to any type of data cartridge. Forexample, the library 100 is capable of being applied to a cartridge witha recording medium that is either a disk, a tape, or a non-movingrecording medium (e.g., a solid state memory). Further, the library 100is capable of being applied to cartridge with a recording medium that ismagnetic, optical, magneto-optical or any other type of recordingmedium. The magazine-based data cartridge library 100 is further capableof being adapted for use with recording mediums that are not located ina cartridge, e.g., CDs.

[0094] In many cases, the magazine-based data cartridge library 100operates on magazine that, unlike the magazines used in cartridge-baseddata cartridge libraries, comprises a structure that allows the magazineto be engaged by the magazine transport 108 so that the transport canmove the magazine within the library.

[0095] With reference to FIGS. 6A-6C, 7A-7B and 8A-8B, an embodiment ofa magazine-based data cartridge library 202 (hereinafter referred to aslibrary 202) is described. Generally, the library 202 is comprised of:(a) an embodiment of a frame 204 for supporting the other elements ofthe library; (b) an embodiment of an entry/exit port 206; (c) anembodiment of a shelf system 208; (d) an embodiment of drives 210; (e)an embodiment of a magazine transport 212; (f) an embodiment of acartridge transport 214; (g) an embodiment of a power supply system 216;(h) an embodiment of a control system 218; and (i) an embodiment of fans220 for cooling the library.

[0096] Before describing the library 202 in greater detail, the datacartridges and magazines that the library 202 is adapted to manipulateare described. The library 202 is adapted for operating on magnetic tapecartridges and magazines that contain the tape cartridges. Specifically,the library 202 is adapted for operating on cartridges that conform tothe following cartridge formats: (a) LTO (linear tape open), (b) SAIT(super advanced intelligent tape, and (c) DLT (digital linear tape).Typically, the library 202 is only used to store magazines that are eachused to hold cartridges with the same cartridge format. For instance,the library 202 may be used to store magazines that are each used tohold LTO tape cartridges. However, the library 202 is capable of storingmagazines that are used to hold cartridges of different types. Forinstance, the library 202 is capable of storing a magazine that holdsLTO tape cartridges and another magazine that holds DLT tapes.Typically, the library 202 is used to store a magazine where themagazine is only used to hold tape cartridges that conform to a singleformat. For instance, the library 202 may be used to store a magazinethat is only used to hold LTO tape cartridges. However, the library 202is capable of storing a magazine that is used to hold cartridges ofdifferent formats. For instance, the library 202 is capable of storing amagazine that is used to hold LTO and SAIT tape cartridges.

[0097] With reference to FIGS. 9A-9B, an LTO tape cartridge 224comprises a first cartridge face 226A, a second cartridge face 226B, afirst cartridge side 228A, a second cartridge side 228B, a firstcartridge end 230A, and a second cartridge end 230B. The distancebetween the first and second cartridge faces 226A, 226B defines theheight of the cartridge, which is 0.85 in. The distance between thefirst and second side surfaces 228A, 228B defines the width of thecartridge, which is 4.15 in. The distance between the first and secondends 230A, 230B defines the depth of the cartridge, which is 4.02 in.The cartridge further comprises an orientation feature 232 that providesa basis for properly orientating the cartridge for insertion in to anLTO tape drive so that data can be read from and/or written to therecording medium within the cartridge. The orientation feature alsoprovides a basis for orienting all of the LTO tape cartridges stored ina particular magazine in the same manner. The cartridge also comprises afirst pair of gripper notches 234A, 234B and a second pair of grippernotches 236A, 236B, with one or both pair of notches typically used by adevice that grips the cartridge during transport between a magazine anda drive.

[0098] With reference to FIGS. 10A-10B, a SAIT tape cartridge 240comprises a first cartridge face 242A, a second cartridge face 242B, afirst cartridge side 244A, a second cartridge side 244B, a firstcartridge end 246A, and a second cartridge end 248B. The distancebetween the first and second cartridge faces 242A, 242B defines theheight of the cartridge, which is 0.85 in. The distance between thefirst and second side surfaces 244A, 244B defines the width of thecartridge, which is 4.15 in. The distance between the first and secondends 246A, 246B defines the depth of the cartridge, which is 4.02 in.The cartridge further comprises an orientation feature 248 that providesa basis for properly orientating the cartridge for insertion in to anSAIT tape drive so that data can be read from and/or written to therecording medium within the cartridge. The orientation feature 248 alsoprovides a basis for orienting all of the SAIT tape cartridges stored ina particular magazine in the same manner. The cartridge also comprises apair of gripper notches 250A, 250B, which are typically used by a devicethat grips the cartridge during transport between a magazine and adrive.

[0099] With reference to FIGS. 11A-11B, a DLT tape cartridge 254comprises a first cartridge face 256A, a second cartridge face 256B, afirst cartridge side 258A, a second cartridge side 258B, a firstcartridge end 260A, and a second cartridge end 260B. The distancebetween the first and second cartridge faces 256A, 256B defines theheight of the cartridge, which is 1.00 in. The distance between thefirst and second side surfaces 258A, 258B defines the width of thecartridge, which is 4.15 in. The distance between the first and secondends 260A, 260B defines the depth of the cartridge, which is 4.16 in.The cartridge further comprises an orientation feature 262 that providesa basis for properly orientating the cartridge for insertion into a DLTtape drive so that data can be read from and/or written to the recordingmedium within the cartridge. The orientation feature in an actual DLT issomewhat more complex than the feature shown in FIG. 11A. Theorientation feature 262 also provides a basis for orienting all of theDLT tape cartridges stored in a particular magazine in the same manner.The cartridge also comprises a single gripper notch 264, which istypically used by a device that grips the cartridge during transportbetween a magazine and a drive. The DLT tape cartridge 306 furthercomprises a recess in the first end 260A that is typically used for tohold a label, such as a bar-code label, that is used to identify thecartridge.

[0100] Generally, the magazine for holding multiple cartridges in amagazine-based data cartridge library comprises a structure that definesa space for holding the cartridges, a partitioning structure fordividing the space into a plurality of slots that are each capable ofaccommodating a data cartridge, and an engagement structure that allowsa magazine transport to engage the magazine so that the magazine can bedisplaced towards and away from a shelf. Typically, the structure iscomprised of a first pair of parallel sides and a second pair ofparallel side that are perpendicular to the first pair of parallelsides. In many cases, the partitioning structure divides the space intoslots that are capable of accommodating a single row of cartridges. Ifdesired, a partitioning structure is feasible that divides the spaceinto slots that are capable of accommodating two or more rows ofcartridges.

[0101] Generally, the magazines employed within the library 202 aredesigned so that when a magazine is operatively situated in the library,any tape cartridges held by the magazine are oriented such that the faceof the cartridge with the greatest surface area lies in a verticalplane.

[0102] With reference to FIGS. 12A-12D, an embodiment of an LTO/SAITmagazine 270 that is capable of accommodating LTO and/or SAIT tapecartridges is described. The magazine 270 comprises: (a) a closed-loopside surface 272 that is comprised of a first and second end sides 274A,274B, and first and second lateral sides 376A, 376B; (b) a bottom side278; and (c) a plurality of partitioning elements 280 that divide aspace defined by the side surface 272 and bottom side 278 into tenslots. The first and second end sides 274A, 274B, and the first andsecond lateral sides 276A, 276B extend between the bottom side 278 andan edge 282 that defines the opening through which cartridges areinserted into and extracted from the magazine. Associated with each slotis an orientation structure 284 that is used to ensure that all of theLTO and/or SAIT cartridges held by the magazine have a predeterminedorientation. FIGS. 13A and 13B respectively illustrate the interactionof the orientation feature 232 of an LTO cartridge with the orientationstructure 284 and the orientation feature 248 of the SAIT cartridge withthe orientation structure 284. Also associated with each slot are firstpair of stand-offs 286A, 286B and a second pair of stand-offs 288A, 288Bthat position the notches of either an LTO or SAIT tape cartridge at adistance from the bottom side 278 that is substantially the same as thedistance between the bottom surface of a DLT tape cartridge magazine andthe notch of a DLT cartridge held therein. Consequently, regardless ofwhether an LTO, SAIT or DLT tape cartridge is presented to the cartridgetransport 214, the notch or notches of the cartridge are atsubstantially the same distance from the bottom of the magazine. Thissimplifies the design of the cartridge transport 214. The distancebetween the first and second end sides 274A, 274B is approximately equalto the distance between the front and backs surfaces of an LTO or SAITdrive, i.e., within about 20% of the distance between the front and backsurface of such a drive.

[0103] Associated with the first end side 274A of the magazine 270 is arecess 290A for accommodating a label that is used to identify themagazine or distinguish the magazine from other magazines in thelibrary. A recess 290B for accommodating an adhesive label is alsoassociated with the second end side 326B. The recesses are associatedwith the first and second end surfaces because, when the magazine isoperatively positioned on a shelf of the shelf system 208 in the library202, either the first end side 274A or the second end side 274B will beexposed or visible so that any label residing in the recess can be read.One alternative to the use of a recess to hold an adhesive label is asleeve or slot structure that can hold a non-adhesive label. Anotheralternative to the use of a recess is a radio frequency identificationtag (RFID tag). An RFID tag can either be substantially permanentlyfixed to the magazine or removable. Further, the RFID tag can eitherhave a permanent identification code or be programmable. Moreover, theRFID tag, unlike a bar-code label, does not necessarily require anunobstructed “line of sight” with a RFID tag reader to be read.Consequently, a single RFID tag may be sufficient.

[0104] The magazine 270 further comprises a first and second rails 292A,292B that are respectively associated with the first and second lateralsides 276A, 276B. With reference to FIG. 12C, the first and second rails292A, 292B are located so as to establish an asymmetry that is used toposition the magazine with a predetermined orientation within thelibrary. More specifically, the first and second rails 292A, 292B areasymmetric with respect to a plane 294 that bisects the magazine 270.The ability to position the magazine 270 with a predeterminedorientation within the library and to position the cartridges held bythe magazine with a predetermined orientation, in turn, substantiallyensures that the cartridges will also be presented to the cartridgetransport 214 in the same orientation. Other structures that establishan asymmetry relative to other planes are also feasible. The rails 292A,292B also facilitate the guiding of the magazine 270 within the library202 (e.g., guiding the magazine to a particular location on a shelf) andprevent the magazine from being displaced in certain directions.Respectively associated with the rails 292A, 292B are notches 295A,295B. The notches 295A, 295B are used with complementary structuresassociated with the magazine transport 212 to hold the magazine 270 inplace when the magazine is associated with the transport.

[0105] With reference to FIG. 12D, associated with the bottom side 278of the magazine 270 are a pair of detents 296A, 296B that cooperate withcomplementary structures associated with a shelf of the shelf system 208to prevent the magazine from being displaced away from a shelf in anuncontrolled manner, i.e., being displaced away from the shelf bysomething other than the magazine transport 212. The detents 296A, 296Band the complementary structures associated with a shelf form a passivelatch (i.e., a latch without any moving parts). A latch can also berealized by swapping the detents and the complementary structures, i.e.,associating the detents with the shelf and the complementary structureswith the magazine. Also feasible is an active latch in which either anelement associated with the magazine or an element associated with theshelf includes a moving component. Typically, the moving elementcomprises an element that operates in a spring-like fashion to allow thelatch to be engaged and disengaged when desired. An example of an activelatch mechanism is disclosed in U.S. Patent Application Publication No.US 2003/0076618 A1.

[0106] The magazine 270 further comprises a first pair of engagementholes 298A, 298B that are utilized by the magazine transport 212 todisplace the magazine 270 towards or away from a shelf in the shelfsystem 208. More specifically, the magazine transport 212 “hooks” theholes 298A, 298B and then pulls and/or pushes the magazine towards oraway from a shelf. Associated with the first pair of engagement holes298A, 298B is a first engagement flag structure 300 that is comprised apair of holes 302A, 302B, that are separated by a bar 304. Theengagement flag structure 300 operates such that when magazine transport212 has engaged the magazine, the bar 304 breaks a beam of light andwhen the magazine transport 212 is not engaging the magazine, the bar304 does not break the beam of light. As an alternative to theengagement flag structure 300, the exterior surface of the bottom side278 of the magazine 270 can be used to indicate when the magazinetransport 212 is engaging the magazine and when the magazine transport212 is not engaging the magazine. To elaborate, the bottom side 278 canbe used as a reflective surface that can be used to determine whether ornot the magazine has been engaged by the magazine transport 212.

[0107] The magazine 270 further comprises a second pair of engagementholes 306A, 306B, and a second engagement flag structure 308 that areused in the same manner as the first pair of engagement holes 298A, 298Band the first engagement flag structure 300. Two sets of engagementholes are utilized because when the magazine is associated with a shelfon one side of the magazine transport 212, the first pair of engagementholes 298A, 298B is accessible but the second pair of engagement holes306A, 306B is not readily accessible. Conversely, when the magazine isassociated with a shelf that is located on the opposite side of themagazine transport 212, the second pair of engagement holes 306A, 306Bis accessible but the first pair of engagement holes 298A, 298B is notreadily accessible. Presently, the magazine 270 has a third pair ofengagement holes 310A, 310B with an associated third engagement flagstructure 312 and a fourth pair of engagement holes 314A, 314B and anassociated fourth engagement flag structure 316 that are capable ofbeing used by the magazine transport 212 to move the magazine but arenot currently utilized. It should be appreciated that other structuresthat are capable of being “hooked” are feasible. For instance, a singlehole is feasible. Also, feasible are one or multiple indentations andone or multiple protrusions. Further, while the magazine transport 212“hooks” the magazine, it should be appreciated that the magazine 270 canbe adapted to facilitate engagement of the magazine by a device thatgrasps the magazine between two arms. Possible structures to facilitategrasping of the magazine comprise a pair of holes in the magazine, apair of indentations in the magazine, and a pair of protrusions thatextend outward from one or more surfaces of the magazine.

[0108] With reference to FIGS. 14A-14B, an embodiment of a DLT magazine320 that is capable of accommodating DLT tape cartridges is described.The DLT magazine 320 is substantially identical to the LTO/SAIT magazine270. Consequently, those elements of the DLT magazine 320 that arecommon to both the DLT magazine 320 and LTO/SAIT 270 are not describedfurther. Further, in describing the DLT magazine 320, elements of theDLT magazine 320 that are substantially identical to elements in theLTO/SAIT magazine 270 will bear the same reference number as thosesubstantially identical elements in the LTO/SAIT magazine 270. The DLTmagazine 320, in addition to the elements that are common to theLTO/SAIT magazine 270, comprises partitioning elements 322 that dividethe interior space of the magazine into nine slots. Associated with eachslot is an orientation structure 324 that is used to ensure that all ofthe DLT cartridges held by the magazine have a predeterminedorientation. FIG. 15 illustrates the interaction of the orientationfeature 262 of a DLT cartridge with the orientation feature 324 of themagazine. It should also be noted that the DLT magazine 320 does notemploy any stand-offs.

[0109] Having described the cartridges and magazines on which thelibrary 202 operates, the general layout of the library 202 is nowdescribed. As shown in FIG. 16, the layout of the library 202 is arectilinear layout that conforms to the specifications for therectilinear layout illustrated in FIG. 2B. More specifically, the shelfsystem 208 comprises five columns of shelving 328A located along a firstplane 330A, two columns of shelving 328B located along a second plane330B, and two columns of drives 332 located along the second plane 330B.The magazine transport 212 and cartridge transport 214 are each locatedin the space between the first and second planes 330A, 330B and eachmove at least within a portion of the space between the first and secondplanes 330A, 330B. Most of the other elements of the library 202 alsoconform to the rectilinear layout. Specifically, the entry/exit port 206is located within the five columns of shelving 328A and along the firstplane 330A; the power supply 216 is located below the two columns ofdrives 332 and either along the second plane 330B or along a parallelplane; the control system 218 is located below the two columns ofshelving 328B and either along the second plane 330B or along a parallelplane; and the fans 220 are located under the five columns of shelving328A and either along the first plane 330A or a parallel plane.

[0110] In addition to the general layout of the library 202, the userhas a choice about the function of certain space in the library 202. Toelaborate and with reference to FIG. 7B, the library 202 comprises auser-definable space 332 with six stations that are each capable ofaccommodating either one of two types of modules. Each of the stationsis capable of accommodating a drive bay module that holds up to fourdrives or a magazine bay module that provides shelving for up to fourmagazines. A user-definable space with less than six stations isfeasible. Further, if multiple stations are employed, each station doesnot need to have the same dimensions. For instance, a station couldaccommodate either only one drive or provide shelving for only onemagazine.

[0111] With reference to FIGS. 6A-6C, 7A-7B and 8A, 8B, the frame 204comprises elements that define the edges of a box-like structure and thesurfaces of the box-like structure. The surfaces comprise a frontsurface 340A, a back surface 340B, a first side surface 340C, a secondside surface 340D, a top surface 340E, and a bottom surface 340F.Associated with the front surface 340A are the entry/exit port 206, anoperator interface 342 that is implemented with a touch screen, and agrill structure 344 that covers the fans 220. Associated with the backsurface 340B are a fixed panel 346 that is located adjacent to a seriesof shelves, a hinged door panel 348 that provides access to the drives210 and the power supply 216, an opening 350 through which an ACcable(s) is/are connected to the power supply 216, and a grill 352 forpromoting air circulation within the library. The first side surface340C is removable so that the library 202 can be cascaded with at leastone add-on unit to expand the library. Also associated with the firstside surface 340C is a first clear panel 354A that allows an operator toview the interior of the library 202. Similarly, a second clear panel354B is associated with the second side surface 340D. The top surface340E includes a pair of knockouts 356A, 356B that can be used to receiveone or more AC cables that are connected to the power supply 216 and/orone or more computer cables that are used to connect the library to ahost computer. Also associated with the top surface 340E is a firesuppression system hole 358 for receiving a nozzle or other device fordispensing a fire retardant into the library 202. Associated with thebottom surface 340F are casters 360A-D that facilitate movement of thelibrary and adjustable stands 362A-D that allow the library to beleveled after the library has been positioned in a relatively permanentlocation. Further associated with the bottom surface 340F are openings364A, 364B for receiving one or more AC cables that are connected to thepower supply 216 and/or a computer cable(s) that are used to connect thelibrary to a host computer.

[0112] The library 202 has a depth of 43.16 in. as measured from thefront surface 340A to the back surface 340B, a width of 30.50 in. asmeasured from the first side surface 340C to the second side surface;and a height of 74.25 in. as measured from the top surface 340E to thebottom surface 340F.

[0113] Generally, the entry/exit port 206 serves to move magazinesbetween: (a) an environment that is exterior to the library 202 andaccessible to a user; and (b) a space located within the library 202 andaccessible by the magazine transport 212. When the entry/exit port 206is exposed to the exterior environment such that an operator can eitherremove a magazine that has been conveyed from the space within thelibrary or place a magazine in the entry/exit port 206 for conveyance tothe space within the library 202, the port 206 is in a first state.Similarly, when the port 206 is exposed to the space located within thelibrary such that the magazine transport 212 can either remove amagazine that is in the space or place a magazine in the space(typically, for conveyance to the exterior environment) the magazine isin a second state.

[0114] With reference to FIGS. 17A and 17B, the entry/exit port 206 iscomprised of a first entry/exit port 368 and a second entry/exit port370 that operates independently of the first entry/exit port 368. Thefirst and second entry/exit ports 368, 370 provide greater throughputthan a single entry/exit port, i.e., more magazines can be moved betweenthe exterior environment and the spaces within the library 202associated with the first and second entry/exit ports 368, 370 over agiven time period than is possible with a single exit/entry port of thesame design. In addition, the first and second entry ports 368, 370provide redundancy. Consequently, if one of the first and secondentry/exit ports 368, 370 should become disabled, the other port can, inmany cases, still be used to transport magazines. A library with asingle entry/exit port is also practicable. With continuing reference toFIGS. 17A and 17B, the entry exit port 206 comprises a chassis 372 withan exterior side 374A that is exposed to the exterior environment oradjacent to the front side 340A and an interior side 374B that isexposed to the magazine transport 212 and is substantially located alongthe plane 330A. In the illustrated embodiment, the first entry/exit port368 is in the second state, i.e., a magazine (such as magazine 376) canbe removed from a space 378 by the magazine transport 212 or a magazine(assuming magazine 376 is no longer present in the space) can beinserted into the space 378 by the magazine transport 212. Conversely,the second entry/exit port 370 is in the first state, i.e., an operatorcan remove a magazine (such as magazine 380) from the port 370 or anoperator can associate a magazine (assuming magazine 380 is no longerpresent) with the port 370 for transport to the space 382.

[0115] The first entry/exit port 368 is substantially identical to thesecond entry/exit port 370. Consequently, the first entry/exit port 368is described with the understanding that the description is alsoapplicable to the second entry/exit port 370. Generally, the firstentry/exit port 368 utilizes a support to move a magazine between: (a) afirst location at which an operator can either associate a magazine withthe support or remove a magazine from the support; and (b) a secondlocation at the magazine transport 212 can either remove a magazine fromthe support or associate a magazine with the support. Further, the firstentry/exit port 368 also utilizes a door system for preventing anoperator from accessing the interior of the library and possibly gettinginjured by one of the moving elements. The door system is comprised ofan interior door and an exterior door. The door system operates suchthat when the support is in the first location, such that an operatorcan either associate a magazine with the support or remove a magazinefrom the support, the exterior door is open and the interior door isclosed or closing to prevent the operator from accessing the interior ofthe library 202. Conversely, when the support is in the second location,such that the magazine transport 212 can either associate a magazinewith the support or remove a magazine from the support, the interiordoor is open to provide the magazine transport 212 with access to thesupport and the exterior door is closed or closing to prevent anoperator from accessing the interior of the library 202.

[0116] With reference to FIGS. 18A-18E, the first entry/exit port 368 isgenerally comprised of: (a) a tray 386 for supporting a magazine; (b) adoor assembly 388 that comprises an exterior door and an interior door,is attached to the chassis 372, and used to support the tray 386; and(c) an actuator system 390 for moving the tray 386, the exterior door,and the interior door.

[0117] The tray 386 is comprised of a bottom side 392, first and secondside walls 394A, 394B, an exterior end wall 396 and a movable end wall398. The bottom side 392, first and second side walls 394A, 394B andexterior end wall 396 define a shallow interior space for supporting amagazine. The first and second side walls 394A, 394B prevent themagazine from moving laterally. The movable end wall 398 prevents amagazine from moving in the direction of movable end wall 398 undercertain conditions but permits a magazine to move in the direction ofthe movable end wall 398 under other circumstances. To elaborate, themovable end wall 398 is moveable between a first position and a secondposition. In the first position, the movable end wall 398 prevents amagazine that is located in the interior space from moving in thedirection of the movable wall 398. The movable end wall 398 performsthis preventive function when the tray 386 is moving between the firstlocation and the second location, e.g., when a magazine is beinginserted into the library 202 from the exterior environment. In thissituation, the magazine acquires momentum that, if the moveable end wall398 were not in the first position, could potentially cause the magazineto slide on the tray and into the space in which the magazine transport212 and cartridge transport 214 operate, potentially damaging thelibrary. In the second position, the movable end wall 398 allows themagazine transport device 212 to either place a magazine on the tray 386or remove a magazine from the tray 386. The movable end wall 398 isplaced in the second position after the tray 386 has been moved to thesecond location, i.e., the location at which the magazine transporter212 is able to either load the tray 386 with a magazine or remove amagazine from the tray 386, or at a time before the tray 386 has reachedthe second location but at which it is unlikely that any momentumimparted to the magazine is likely to carry the magazine into themagazine transporter 212 or cartridge transport 214 operational space.

[0118] Associated with the bottom side 392 of the tray 386 is a linearrail 400 that mates with a rail block located on the door assembly 388to allow the tray 386 to slide between the first and second locations.Also associated with the bottom side 392 is a sensor assembly 402 thatis used to sense the possible presence of a magazine in the interiorspace of the tray 386 and a flex cable 404 that allow the signalsproduced by the sensor assembly 402 to be conveyed to the control system218. Further associated with the bottom side 392 is a pair of brackets406A, 406B to which the movable end wall 398 is mounted.

[0119] Associated with the first and second side walls 394A, 394B areguides 408A, 408B that form part of a linkage that is used to move theexterior and interior doors between the open and closed positions. Afirst pair of end blocks 410A, 410B are located at the ends of theguides 408A, 408B that are located adjacent to the exterior end wall396. A second pair of end blocks 412A, 412B are located at the ends ofthe guides 408A, 408B that are located adjacent to the movable end wall398. A drive block 414 that is used to receive the motive forces fromthe actuator system 390 that cause the tray 386 to slide between thefirst and second locations is associated with the first side wall 394A.Also associated with the first side wall 394A is an orientation feature416 that is used in conjunction with the rails 292A, 292B of a magazineto substantially ensure that a magazine that an operator places in theinterior space of the tray 386 has a desired orientation. To elaborate,if an operator places a magazine in the interior space of the tray 386with magazine oriented such that the rails 292A is disposed adjacent tothe orientation feature 416, the magazine is properly oriented and thebottom side 278 of the magazine lies flush with the bottom side 392 ofthe tray. If, however, an operator places a magazine in the interiorspace of the tray 386 with the magazine oriented such that the rail 292Bis disposed adjacent to the orientation feature 416, the magazine is notproperly oriented and the bottom side 278 of the magazine will not lieflush with the bottom side 392 of the tray. Further, the sensorsassociated with the sensor assembly 402 are able to detect thiscondition and provide the control system 218 with this information sothat the control system 218 can prevent the tray 386 from being moveduntil the magazine is properly oriented. In one embodiment, the sensorassembly 402 comprises two optical sensors that are disposed laterallyacross the tray. Another sensor is operatively attached to the chassisadjacent to the exterior door and operates to sense the presence of anobject adjacent to the door. The signals produced by the two opticalsensors and the door sensor are capable of being used to determine if amagazine is not present in the tray 386, if a properly loaded magazineis present in the tray 386, an improperly loaded magazine is present inthe tray 386, or something other than a magazine is present in oradjacent to the tray 386

[0120] Associated with the exterior end wall 396 is a sloped surface 418that facilitates insertion of a magazine into the interior space of thetray 386 when the tray is in the first location. The sloped surface 418terminates before reaching the bottom side 392 so that a corner 419 isformed for receiving the corner formed by the end side 274A and bottomside 278 of a magazine. Further, when the movable end wall 398 is in thefirst position and a magazine is in the interior space of the tray 386,the magazine is clamped between the corner 419 and the movable end wall398.

[0121] The movable end wall 398 is comprised of an S-shaped member 420that is pivotally attached to the brackets 406A, 406B. A spring (notshown) biases the S-shaped member 420 so that the S-shaped member 420 isin the first position, as shown in FIG. 18C, to prevent a magazine fromentering the operational space of the magazine transport 212 andcartridge transport 214 in an uncontrolled fashion. The S-shaped member420 further comprises a camming surfaces 424A, 424B that cooperate withcamming elements associated with the door assembly 388 to move theS-shaped member 420 into the second position, shown in FIG. 19E, so thatthe magazine transport 212 can either remove a magazine from the tray386 or associate a magazine with the tray 386.

[0122] With reference to FIG. 18D, the door assembly 388 comprises adoor mounting plate 428, exterior door 430A, and an interior door 430B.The exterior door 430A is pivotally connected to the door mounting plate428 via mounting blocks 432A, 432B, which constrain the exterior door430A to rotate about a horizontal axis. The exterior door 430A comprisesfirst and second connection flanges 434A, 434B for establishing pivotalconnections with a linkage that is used to move the door. Similarly, theinterior door 430B is pivotally connected to the door mounting plate 428via mounting blocks 436A, 436B, which constrain the interior door 430Bto rotate about a horizontal axis. The interior door 430B comprisesfirst and second connection flanges 438A, 438B for establishing pivotalconnections with a linkage that is used to move the door. Alsocomprising the door assembly 388 is a rail block 440 that cooperateswith the linear rail 400 of the tray 386 to allow the tray to slidebetween the first and second locations. The door assembly 388 furthercomprises a pair of cam elements 442A, 442B that interact with a cammingsurfaces 424A, 424B associated with the movable end wall 398 to move theS-shaped member 420 to the second position so that the magazinetransport 412 can either remove a magazine from the tray 386 or place amagazine on the tray 386.

[0123] The actuator system 390 operates to move the tray 386 between thefirst and second positions and to move the exterior and interior doors430A, 430B between open and closed positions. Moreover, the actuatorsystem 390 coordinates the opening and closing of the interior doors430A, 430B with the movement of the tray 386 between the first andsecond positions. To elaborate, the actuator system 390 operates suchthat during the time that the tray 386 is moving from the first locationto the second location (e.g., when a magazine is being inserted into thelibrary 202), the exterior door 430A moves between open and closedpositions and the interior door 430B moves between closed and openpositions. Conversely, the actuator system 390 operates such during thetime that the tray 386 is moving from the second location to the firstlocation (e.g., when a magazine is being extracted from the library),the exterior door 430A moves between closed and open positions and theinterior door 430B moves between the open and closed positions.

[0124] The actuator system 390 comprises a pair of brackets 446A, 446Bthat support a lead screw 448, a nut 450 that is attached to the leadscrew 448 and has a post that engages a hole in the drive block 414, anelectric motor 452, and a pair of gears 454A, 454B that transmit arotational force produced by the electric motor 452 to the lead screw448. Further comprising the actuator system 390 is a first pair ofslotted blocks 456A, 456B (see FIG. 19A) that are operatively associatedwith the guide 408A. A second pair of slotted blocks 458A, 458B areoperatively associated with the guide 408B. The actuator system 390further comprises a first pair of links 460A, 460B that respectively,pivotally connect the first connection flange 434A of the exterior door430A with the slotted block 456A and the first connection flange 438A ofthe interior door 430B with the slotted block 456B. Similarly, a secondpair of links 462A, 462B respectively, pivotally connect the secondconnection flange 434B of the exterior door 430A with the slotted block458A and the second connection flange 438B of the interior door 430Bwith the slotted block 458B. The position of the tray 386 is provided bya detector that operates to detect the presence of a flag associatedwith the tray when the tray is at a home position and an encoderassociated with the motor 452. Other position detecting schemes arefeasible.

[0125] With reference to FIGS. 19A-19F, the operation of the entry/exitport 368 in moving a magazine 466 between an environment in which thetray 386 is accessible by an operator to a space that is accessible tothe magazine transport 212 (i.e., in direction 468) is described.

[0126] With reference to FIG. 19A, the entry/exit port 368 is in thefirst state, i.e., the tray 386 is at a location at which an operatorcan associate a magazine with the tray 386. For illustration, themagazine 466 has been associated with the tray 386. In this regard, thespring associated with the movable end wall 398 has placed the S-shapedmember 420 in the first position. As a consequence, the magazine 466 isprevented from sliding in the direction 468. Further, the magazine 466is clamped between the corner 419 and the S-shaped member 420. At thispoint, the exterior door 430A is open and the interior door 430B isclosed. Additionally, the slotted block 456B is either contacting therail end block 412A or very close to the rail end block 412A.

[0127] With reference to FIG. 19B, the actuator system 390 has begun tomove the tray 386 in the direction 468, the exterior door 430A is stillopen and the interior door 430B has moved from the closed positiontowards the open position. More specifically, the electric motor 452 hasbeen used to produce a rotational force that has been transmitted by thepair of gears 454A, 454B to the lead screw 448. The rotation of the leadscrew 448 has caused the nut 450 to move towards the electric motor 452.The nut 450, in turn, has applied a force to the tray 386 via the driveblock 414 that has caused the tray 386 to slide over the rail block 440and towards the electric motor 452. As the tray 386 has moved towardsthe electric motor 452, either gravity or contact with the tray 386 hascaused the interior door 430B to begin rotating towards the openposition. However, interaction between the rail end block 412A and theslotted block 456B, which is connected to the interior door via the link460B, has controlled the movement of the interior door 430B.

[0128] With reference to FIG. 19C, the actuator system 390 has continuedto move the tray 386 in the direction 468, the exterior door 430A isstill in the open position and the interior door 430B is now also in theopen position. More specifically, the electric motor 452 has continuedto move the tray 386 in the manner described with respect to FIG. 19B.Further, the interaction between the rail end block 412A and the slottedblock 456B has continued to control the movement of the interior door430B between the closed position and the open position.

[0129] With reference to FIG. 19D, the actuator system 390 has continuedto move the tray 386 in the direction 468, the exterior door 430A hasnow begun to move from the open position towards the closed position,and the interior door 430B remains in the open position. Morespecifically, the electric motor 452 has continued to move the tray 386in the manner described with respect to FIG. 19B. In addition, themovement of the tray 386 has caused the rail end block 410A to beginapplying a motive force to the slotted block 456A. In turn, the slottedblock 456A, due to the connection with the exterior door 430A via thelink 460A, has begun to cause the exterior door 430A to rotate towardsthe closed position.

[0130] With reference to FIG. 19E, the actuator system 390 has continuedto move the tray 386 in the direction 468, the exterior door 430A is nowin the closed position, the interior door 430B remains in the openposition, and the S-shaped member 420 has been moved to the secondposition so that the magazine transport 212 can engage the magazine 466.More specifically, the electric motor 452 has continued to move the tray386 in the manner described with respect to FIG. 19B. In addition, themovement of the tray 386 has caused the rail end block 410A to continueapplying a motive force to the slotted block 456A. In turn, the slottedblock 456A, due to the connection with the exterior door 430A via thelink 460A, has caused the exterior door 430A to rotate to the closedposition. In addition, the movement of the tray 386 has caused the camelements 442A, 442B to engage the camming surfaces 424A, 424B of theS-shaped member 420 and rotate the S-shaped member such that themagazine 466 can be removed from the tray 386 by the magazine transport212. At this point, the entry/exit port 368 is in the second state.

[0131] It should be appreciated that to extract a magazine from thelibrary 202 using the entry/exit port 368, the sequence of operationsillustrated in FIGS. 19A-19E is reversed.

[0132] It should also be appreciated that the entry/exit port 368 iscapable of being modified in a number of ways, provided a magazinetransport is provided that is able to place a magazine in the port orremove a magazine from the port. The following sets forth some of theseother embodiments. For example, the tray 386 is a support for a magazinethat primarily supports a magazine from below. Depending upon the designof a magazine, a support that contacts one or both of the sides of amagazine or the top surface of a magazine is feasible. Further, the tray386 employs the orientation feature 416 to substantially ensure thatmagazines that employ the asymmetrical rails 292A, 292B are properlyinserted into the tray 386. The entry/exit port 368 is capable of beingadapted to magazines that employ a different orientation feature.

[0133] Additionally, structures other than the movable end wall 398 canbe employed to prevent undesired movement of a magazine. For instance, adevice that clamps the side surface of the magazine can be employed. Ifa particular magazine design has top and bottom surfaces, a device thatclamps these surfaces is also feasible. Another alternative topreventing undesired movement of a magazine is to provide a structurethat engages a feature of the magazine, such as a hole, indentation orprotrusion. Further, a movable end wall in which the magazine transport,rather than the entry/exit port, causes the wall to move betweenpositions is feasible.

[0134] Furthermore, while the actuation system 390 employs the electricmotor 452 and linkages to cause the tray 386, exterior door 430A, andinterior door 430B to move in a coordinated fashion, other approachesare feasible. For example, a system in which separate electrical motorsor other motive components (such as solenoids) are associated with themagazine support and each of the doors is feasible. In this case,coordination of the movements of the tray and the doors is achieved bycontrolling the motors or other motive components. Similarly, a systemin which an electrical motor or other motive component is associatedwith the magazine support and another motor or motive component isassociated with the combination of the two doors is feasible. In thiscase, the operation of the two doors is coordinated by a mechanicallinkage extending between the doors, and the movements of the supportand the doors is coordinated by appropriately controlling the motors orother motive components. It should also be appreciated that designsemploying linear actuators (such as solenoids) are feasible. Further,other approaches for moving the magazine holder or support, such as abelt-and-pulley and rack-and-pinion systems, are feasible.

[0135] Additionally, while the entry/exit port 368 employs planar doorsthat each rotate about horizontal axes that are parallel to the planesof the doors, many other designs are feasible. For example, designs inwhich a door rotates about an axis that is parallel to the plane of thedoor but not a horizontal axis (e.g., a vertical axis) is feasible.Designs in which a door rotates about an axis that is substantiallyperpendicular to the plane of the door are also feasible. An example ofsuch a design is shown in FIG. 20A. In this design, both an exteriordoor 472A and an interior door 472B that resides in a plane that issubstantially parallel to the plane of the exterior door 472A rotateabout an axis that is perpendicular to the planes of both of the doors.In addition, the exterior door 472A and the interior door 472B areangularly or rotationally offset. Coordination of the opening andclosing of the doors is achieved by a rod 474 that connects the doors.It should be noted that with such a design, the exterior door 472A andthe interior door 472B move simultaneously. Consequently, when one ofthe doors is moving from the open position to the closed position, theother door is moving from the closed position to the open position. Alsofeasible are designs in which a door is linearly translated between openand closed positions, rather than rotated between open and closedpositions. An example of such a design is shown in FIG. 20B. In thisdesign, a door 476 is disposed between a pair of guides 478A, 478B thatconstrain the door 476 to move linearly between open and closedpositions. A linkage 480 is used to apply the forces needed to move thedoor 476 between open and closed positions. In FIG. 20B, the door 476 isin an open position so that a magazine 482 can pass through the doorstructure. Also feasible are door designs in which a door is comprisedfor two or more elements. An example of such a design is shown in FIG.20C. In this design, a door structure 484 is comprised of a pair ofdoors 486A, 486B that are constrained to move linearly by guides 488A,488B. A linkage 490 is used to transmit the forces that cause the doors486A, 486B to move: (a) towards each other to achieve a closed position,and (b) away from each other to achieve an open position. Furtherfeasible are doors that employ non-planar doors. An example of such adesign is shown in FIG. 20D. In this design, a curved door 492 isconstrained to rotate about an axis 494 by a pair of curved guides 496A,496B and a linkage 498. Also feasible is a “roll top” door. An exampleof door structure that utilizes roll top doors is shown in FIG. 20E. Inthis design, a door structure 500 is comprised of a pair of roll-topdoors 502A, 502B that are connected to one another by a flexible cablestructure 504. A guide structure 506 defines a track around which thedoors 502A, 502B. This design also allows for overlap in the timesduring which one of the doors is transitioning between an open positionand a closed position and the other door is transitioning between aclosed position and an open position.

[0136] While the entry/exit port 368 employs a movable tray 386, anentry/exit port that employs a cartridge holder that does not move isalso feasible.

[0137] An alternative to an entry/exit port that employs a pair of doorsis a carousel entry/exit port. An example of a carousel entry/exit portis shown in FIGS. 21A-21B. In this design, a carousel entry/exit port508 is comprised of a housing 510 that defines a port 512 for holding amagazine. The housing 510 rotates about an axis 514. Rotation isaccomplished by an electric motor (not shown). In operation, thecarousel exit/entry port 508 rotates between a first location at whichan operator can either remove a magazine from the port 512 or associatea magazine with the port 512 and a second location at which a magazinetransport device can either remove a magazine from the port 512 orassociate a magazine with the port 512.

[0138] Generally, the shelf system 208 serves to support magazines inthe library 202 in a preferred or desired orientation. The shelf system208 orients magazines in the library such that: (a) the magazines areparallel to one another: (b) any cartridges contained in the magazinesare oriented to facilitate insertion and extraction by the cartridgetransport 214; and (c) a high data density footprint is achieved.Furthermore, the shelf system 208, each of the shelves comprising theshelf system 208 is capable of supporting multiple magazines. However, ashelf system with a shelf that is only capable of accommodating a singlemagazine is feasible.

[0139] With reference to FIG. 16, the shelf system 208 is comprised ofthe five columns of shelving 328A and the two columns of shelving 328B.With reference to FIGS. 7A-7B and 8A-8B, the five columns of shelving328A are realized by ten, horizontally extending shelves that are eachcapable of supporting up to five magazines and three, horizontallyextending shelves that are each capable of supporting up to threemagazines. The two columns of shelving 328B are realized by twelve,horizontally extending shelves that are each capable of supporting up totwo magazines.

[0140]FIG. 22A illustrates a shelf 518 that is capable of accommodatingup to five magazines. Shelf 518 is described with the understanding thatthe description is also applicable, with appropriate modifications, tothe shelves that are capable of accommodating different numbers ofmagazines, such as the shelves in the library 202 that are capable ofaccommodating up to three magazines and up to two magazines. The shelf518 comprises a planar member 520 for supporting magazines fromunderneath. The shelf further comprises six cleats 522A-F that serve anumber of purposes. Specifically, the cleats 522A-F: (a) divide theshelf 518 into five cells, each of which is capable of accommodating asingle magazine; (b) constrain any magazines supported by the shelf 518to be oriented substantially parallel to one another; (c) constrain anymagazines supported by the shelf 518 to be oriented such that anycartridges in the magazines are all oriented in the same manner tofacilitate insertion and extraction of the cartridges by the cartridgetransport 214; (d) prevent, due to the spacing between consecutivecleats, lateral displacements (i.e., displacements along the x-axis) ofany magazines supported by the shelf 518; (e) prevent verticaldisplacements (i.e., displacements along the z-axis) of any magazinessupported by the shelf 518; (f) resist undesired horizontaldisplacements (i.e., displacements along the y-axis) of a magazinesupported by the shelf 518; (g) constrain the direction that a magazineis either moved towards the shelf or away from the shelf to horizontaldisplacements (i.e., displacements along the y-axis).

[0141] With reference to FIG. 22B, the cleat 522A is described with theunderstanding that the description is also applicable to cleats 522B-F.The cleat 522A is comprised of a dual guide structure 524 with an upperguide 526A for receiving the rail 292A of a magazine and a lower guide526B for receiving the rail 292B of a magazine. The cleat 522A alsocomprises prongs 528A-528D that engage holes (not shown) in the planarmember 520 and operate to hold the cleat 522A in place on the planarmember 520. Additionally, the cleat 522A comprises a receptacle 530(which also extends away from the side of the cleat 524 not seen in FIG.22B) for accommodating one of the detents 296A, 296B associated with amagazine, and when accommodating one of the detents, operating to resistundesired horizontal displacements of the magazine. The cleat 522A alsocomprises an end surface 532 that is detectable by the magazinetransport 512 and facilitates positioning of the magazine transport 512relative to the shelf 512 and relative to a particular magazinesupported by the shelf. The end surface 532 presently has a reflectivecharacter that makes the end surface distinguishable from the adjacentfeatures. A contrasting color approach is also feasible, as well as atactile approach.

[0142]FIG. 22C demonstrates the manner in which two cleats cooperate toachieve some of the previously noted purposes. The operation of cleats522B and 522C on a magazine 534 is described with the understanding thatother pairs of cleats operate in a substantially similar manner. Thecleats 522B and 522C are spaced from one another such that the upperguide 526A of cleat 522B captures the rail 292A of the magazine 534 andthe lower guide 526B of the cleat 522C captures the rail 292B of themagazine 534. As a consequence, the cleats 522B and 522C cooperate toprevent the magazine 534 from being laterally and vertically displaced.Additionally, the cleats 522B, 522C limit displacements of the magazine534 to horizontal displacements along the y-axis. Although not shown inFIG. 22C, it should be appreciated that the detents 296A, 296B of themagazine 534 are respectively engaging the receptacle 530 associatedwith the cleat 522B and the receptacle 530 associated with the cleat522C to prevent undesired horizontal displacements of the magazine 534.Further, the cleats 522B, 522C cause the magazine 530 to be orientedsuch that a cartridge 536 has a particular orientation on the shelf 518and within the library 202. To elaborate, as previously noted, eachmagazine has an orientation structure associated with each slot thatsubstantially ensures that all of the cartridges stored by the magazinehave the orientation in the magazine. The rails of the magazines 292A,292B cooperate with the guides 526A, 526B associated with a pair ofcleats to substantially ensure that the magazine has a particularorientation on the shelf 518. As a consequence, the guides 526A, 526Balso substantially ensure that the cartridge 536 has a particularorientation on the shelf 518 and within the library 202. Further, sinceall of the cleats 522A-522F are oriented on the planar member 520 in thesame way, all of the magazines supported by the planar member 520 havethe same orientation and all of the cartridges contained by all of themagazines have the same orientation, as shown in FIG. 22A. It should befurther appreciated that the shelf 518 and the magazine 534 cooperatesuch that the cartridge 536 is oriented in the library such that thefaces of the cartridge 536 with the greatest surface areas (in thisparticular case, faces 242A, 242B of the SAIT data cartridge) each lie avertical plane. Moreover, each pair of cleats substantially ensures thecartridges contained in any magazines are oriented such that the facesof the cartridge with the greatest surface areas each lie in a verticalplane that is substantially perpendicular to the axis or direction inwhich the cleats allow the magazine to be displaced, namely, along they-axis. Orienting the cartridges in this manner contributes to a highdata density footprint.

[0143] With continuing reference to FIG. 22C, it should also beappreciated cleats 522B and 522C each serve as a guide for a magazinethat may be disposed on the planar member 520 adjacent to the magazine534. To elaborate, the upper guide 526A of cleat 522B serves to capturethe rail 292A of the magazine 534 and the lower guide 526B of the cleat522B will serve to capture the rail 292B of any magazine that isdisposed on the planar member 520 immediately adjacent to one side ofthe magazine 534. Likewise, the lower guide 526B of the cleat 522Cserves to capture the rail 292B of the magazine 534 and the upper guide526A of the cleat 522C will serve to capture the rail 292A of anymagazine that is disposed on the planar member 520 immediately adjacentto the other side of the magazine 534.

[0144] With reference to FIGS. 7A-7B and 8A-8B, each shelf of the shelfsystem 208 that has an immediately overlying shelf is vertically spacedfrom the immediately overlying shelf by a distance that is only slightlygreater than the distance between the bottom side 278 of the magazineand the surface associated with a cartridge that is properly located inthe magazine and furthest from the bottom side 278 of the magazine. Thisspacing between shelves also contributes to achieving a high datadensity footprint.

[0145] It should also be appreciated that the shelf system 208 iscapable of being modified in a number of ways. The following sets forth,without limitation, some possible modifications or alternativeembodiments. For example, a shelf system is feasible in which each shelfis capable of supporting only a single magazine. Also feasible is ashelf system that employs a structure other than a planar member tosupport one or magazines. For instance, a shelf that utilizes two,L-shaped brackets to support a magazine is feasible. Further, a shelfsystem in which a shelf provides support to a magazine other than from alocation below the magazine is also practicable. Depending upon thedesign of a magazine, a shelf that provides support to: (a) one side ofthe magazine; (b) both of sides of a magazine; or (c) the top surface ofa magazine is feasible. A shelf that is tilted to prevent undesireddisplacements of a magazine is also practicable. Such a shelf wouldavoid the need for a latch structure, such as receptacle 530. Further, ashelf that incorporates an active latch or retention structure that isactuated by a magazine transport is also possible. A shelf system inwhich there is greater vertical spacing between shelves is practicablebut in most cases will compromise the data density footprint of thelibrary. Further, the shelf system 208 holds magazines in a grid arrayor X-Y array. A shelf system 208 that holds magazines in differentarrays is also feasible. Another embodiment of a shelf system comprisesone or more fixed slots each for holding a cartridge. Among the types ofcartridges that can be held in such a fixed slot is a “cleaning”cartridge, i.e., a cartridge that is used to hold a cartridge that isadapted to clean the heads associated with a drive.

[0146] As shown in FIG. 8B, each of the drives 210 has a horizontalorientation with the long dimension of the receptacle for receiving acartridge extending horizontally. It should be appreciated that it isfeasible for each of the drives to have a different orientation, such asvertical orientation. It is also possible to have one or more driveswith one orientation and one or more drives with a differentorientation. It should also be appreciated that the orientation ororientations of the drives, the orientation or orientations ofcartridges stored in the library 202, and the orientations of the drivesrelative to the cartridges generally dictate the manner in which thecartridge transport must manipulate the cartridges.

[0147] Each of the drives 210 is also one of an LTO, SAIT and DLT tapedrive. Typically, all of the drives are one of an LTO, SAIT and DLT tapedrive. The library 202 is capable of being adapted to accommodate othertape drives. Moreover, the library 202 is adaptable to drives thatoperate on other types of cartridges, such as disk cartridges.

[0148] With reference to FIG. 8B, the library 202 is capable ofaccommodating up to twenty-four, full height drives, where each of thedrives is one of an LTO, SAIT or DLT tape drive. The library 202 is alsocapable of accommodating up to forty-eight, half-height drives, whereeach of the drives is one of an LTO, SAIT or DLT tape drive. The library202 is capable of being modified to accommodate greater or lessernumbers of drives. However, the library 202 must have at least one driveto be functional. Also feasible are combinations of full-height andhalf-height drives.

[0149] Each of the drives 210 in the library 202 is mounted in a drivebay assembly that provides the ability to relatively quickly mount anddemount a drive from the library. Generally, this ability is achievedusing: (a) a sled that is capable of holding a drive; (b) a housing forreceiving the sled; and (c) a plug structure that allows a drive thathas been attached to a sled to be mounted by inserting the sled into thehousing and demounted by removing the sled from the housing.

[0150] With reference to FIGS. 23A-23C, an embodiment of a drive bayassembly 540 is described. The drive bay assembly 540 is capable ofaccommodating up to four, full-height drives or up to eight, half-heightdrives, and various combinations of full-height and half-height drives.The drive bay assembly 540 is mounted to a ladder frame 542 that definessix compartments 544A-544F that are each capable of accommodating one ofthe drive bay assembly 540. Generally, when the drive bay assembly 540is mounted in one of the compartments 544A-544F and a drive is mountedin the drive bay assembly 540, the receptacle of the drive is positionedso that the cartridge transport 214 can insert a cartridge into andextract a cartridge from the drive. The sled holding the drive isaccessible to an operator by opening the hinged door 348. Consequently,the operator is able to remove the sled and associated drive from thelibrary without substantial exposure to the magazine transport 212 orcartridge transport 214. Similarly, the operator is also able to inserta sled and a drive into the library without having any substantialexposure to the magazine transport 212 or the cartridge transport 214.FIG. 23A illustrates the drive bay assembly 540 populated with fourdrives 546A-546D that, if the drive bay assembly 540 were mounted to theladder frame 542, would be positioned for insertion and extraction ofcartridges by the cartridge transport 214. Similarly, FIG. 23Billustrates the drive bay assembly 540, with the assembly's four sleds548A-548D that, if the drive bay assembly 540 were mounted to the ladderframe 542, would be positioned for extraction and insertion operationsby an operator.

[0151] With reference to FIGS. 24A-24F, the drive bay assembly 540 iscomprised of a housing 550 that defines four drive bays 552A-552D thatare each capable of accommodating a single drive. The housing 550 alsodefines a quad unit interface processor bay 554 for holding a quad unitinterface processor (“QIP”) that is used to receive power, control anddata signals and distribute the signals to any drives residing in thehousing 550. The housing 550 further includes a first mounting flange556 with a first pair of notches 558A, 558B and a second mounting flange560 with a second pair of notches 562A, 562B. The first pair of notches558A, 558B and second pair of notches 562A, 562B respectively correspondwith a first pair of threaded holes 564A, 564B and a second pair ofthreaded holes 566A, 566B associated with each compartment of the ladderframe 542. To mount the drive bay assembly 540 to the ladder frame 542,the notches 558A, 558B of the mounting flange 556 and the notches 562A,562B of the mounting flange 560 are respectively aligned with thethreaded holes 564A, 564B, 566A and 566B of the ladder frame 542 andthen bolts or screws are used to secure the drive bay assembly 540 tothe ladder frame 542. Demounting of the drive bay assembly 540 from theladder frame 542 accomplished by removing the bolts or screws.

[0152] The drive bays 552A-552D are substantially identical to oneanother. Consequently, only drive bay 552B is described with theunderstanding that the description is also applicable to the other drivebays. Drive bay 552B is comprised of a top wall 570A, a bottom wall570B, a first side wall 570C, and a second side wall 570 that define aninterior space 572 for accommodating a sled, a first open side 574A, anda second open side 574B. When the drive bay assembly is mounted in thelibrary 202, the first open side 574A is adjacent to the space withinwhich the cartridge transport 214 operates and the second open side isadjacent to the hinged door panel 348. Associated with the first openside 574A are a pair of alignment pins 576A, 576B that cooperate with apair of alignment holes associated with the sled to align the sled inthe bay 552B. Associated with the bottom wall 570B is a sled guide 578.The sled guide 578 comprises a base member 580 and two side members582A, 582B that cooperatively form a guide for a sled. The base member580 also defines a plug notch 584 that accommodates a plug that is alsoassociated with the bottom wall 570B. The base member 580 is supportedabove the bottom wall 570B to form a space for accommodating theconductors that provide power, control and data signals to a driveassociated with a sled. A spring-loaded flag 586 is attached to the basemember 580. In operation, the spring associated with the flag 586 causesthe flag to be oriented as shown in FIG. 24C when no sled is associatedwith the drive bay 552B. In this orientation, the flag 586 prevents orinhibits an operator from reaching through the drive bay 552B and intothe space where the magazine transport 212 and/or cartridge transport214 could possibly injure the operator. When a sled is inserted into thedrive bay 552B, the insertion of the sled causes the flag 586 to rotatetowards the base member 580. Also associated with the bottom wall 570Bis a plug assembly 588 that comprises a first female plug 590A forreceiving one or more power-related signals for a drive, a second femaleplug 590B for receiving control and/or data signals for a drive, and amulti-conductor ribbon cable 592 for conveying the power-related signalsand the control and/or data signals to and from the QIP.

[0153] The QIP bay 554 has a front side wall 594A, top side wall 594B,bottom side wall 594C, first side wall 594D, and second side wall 594E.The front side wall 594A accommodates a plug interface (not shown) thatmates with a plug interface associated with the QIP and with one or moreplugs (not shown) that is/are connected to the ribbon cables associatedwith the plug assemblies of each of the drive bays 552A-552D. The secondside wall 594E and the first side walls associated with the drive bays552A, 552C respectively define gaps for the ribbon cables associatedwith the plug assemblies of each of the drive bays. The gap 596Areceives the ribbon cables associated with the plug assemblies of drivebays 552A, 552B. The gap 596B receives the ribbon cables associated withthe plug assemblies of drive bays 552C, 55D. The ribbon cable 592associated with the drive bay 552B extends through a passageway 598A andunder the base member of the sled guide associated with drive bay 552Ato reach the gap 596A. Similarly, the ribbon cable associated with thedrive bay 552D extends through the passageway 598B and under the basemember of the sled guide associated with drive bay 552C to reach the gap596B.

[0154] The drive bay assembly 540 further comprises the four sleds548A-548D, which are substantially identical to one another.Consequently, only sled 548A is described with the understanding thatthe description is also applicable to sleds 548B-548D. Before describingthe sled 548A, the plug interface associated with a typical drive isdescribed. With reference to FIG. 25, the typical drive 190 (see FIGS.5A-5C) comprises a back surface 602 that typically comprises a powerplug 604 for receiving a power signal (typically, +5V and +12V signals)and a control/data plug 606 for receiving control signals and datasignals. In the absence of the drive bay assembly 540, the drive 190would be oriented in the library such that the receptacle 186 would beaccessible by the cartridge transport 214. Typically, the drive 190would also be fixed to a frame within the library with screws thatengage a first pair of threaded holes 608A, 608B associated with thethird surface 190B of the drive and a second pair of threaded holes (notshown) associated with the opposite surface of the drive. In such asituation, removal of the drive 190 from the library would require that:(a) the cable that provides power to the drive 190 be disconnected fromthe power plug 604, which typically involves unscrewing screws orunlatching latches in addition to manipulating the cabling; (b) thecable that provides control and data signals to the drive 190 bedisconnected from the control/data plug 606, which also typicallyinvolves unscrewing screws or unlatching latches in addition tomanipulating the cabling; and (c) the screws connecting the drive to theframe be removed.

[0155] With the foregoing description of the plug interface of a typicaldrive and the manner in which the drive is typically fixed in place in alibrary in mind, the sled 548A generally serves to: (a) provide astructure to which a drive can be fixedly mounted; and (b) provide aplug interface for the drive that faces the opposite direction from pluginterface associated with the drive. As a consequence, when the sled548A is used in combination with the drive bay 552A or any other drivebay of the housing 550, a drive held by the sled 548A can be removedfrom the library 202 without having to undo screws or other fasteners,as required by the conventional approach. Further, when the sled 548Aand an associated drive are removed from the library 202, the electricalconnections with the drive are severed by removing the sled 548A fromthe drive bay. Conversely, a drive can be inserted into the libraryusing the sled 548A and a drive bay without having to manipulate screwsor fasteners in the manner required by the conventional approach.Further, during such an insertion, the electrical connections for theare established by inserting the sled 548A into the drive bay.

[0156] With reference to FIGS. 26A-26C, the sled 548A comprises ahousing 612 that is capable of accommodating a full-height LTO, SAIT orDLT tape drive or two, half-height LTO, SAIT or DLT tapes drives. Thehousing 612 comprises a top wall 614A, bottom wall 614B, first side wall614C, and second side wall 614D that define an interior space 616 forholding a full-height drive or two, half-height drives and an opening618 for receiving the drive or drives into the interior space.Associated with the first side wall 614C are three pairs of holes 620A,620B, 622A, 622B, 624A and 624B. Similarly, associated with the secondside wall 614D are three pairs of holes 626A, 626B, 628A, 628B, 630A and630B. These holes allow most, if not all, of the presently known LTO,SAIT and DLT tape drives, both full-height and half-height, to bemounted in the housing 612. Also, associated with the second side wall614D is a reference flag 632 for use by the magazine transport 212and/or the cartridge transport 214 in locating a sled 548A and any driveheld by the sled. Associated with the bottom wall 614B are a pair ofrails 634A, 634B. The rails 634A, 634B are spaced so as to be receivedby the guide formed by the base member 580 and two side members 582A,582B of the sled guide 578. The rails 634A, 634B respectively includereceptacles 636A, 636B. The receptacles 636A, 636B respectively receivethe alignment pins 576A, 576B when the sled is properly inserted into adrive bay. A hole 638 that provides access to a “tape wind” screw of adrive located in the housing 612 is also associated with the bottom wall614B of the housing 612.

[0157] The sled 548A further comprises a back wall assembly 640 thatadjoins the top wall 614A, bottom wall 614B, first side wall 614C, andsecond side wall 614D. The back wall assembly 640 comprises a housing642 that supports a plug structure 644 for connecting a drive held bythe housing 612 with the plug assembly 588 associated with any one ofthe drive bays 552A-552D. The plug structure 644 comprises: (a) a firstplug interface 646 that is located to engage the plug assembly 588associated with a drive bay when the sled 548A is properly aligned andinserted into the drive bay; (b) a second plug interface 648 for engagethe plug interface associated with the back surface of a drive; and (c)conductors 650 extending between the first and second plug interfaces646, 648. More specifically, the first plug interface 646 comprises afirst power plug 652A and a first data/control plug 652B that arerespectively located to engage the power plug 590A and data/control plug590B of the plug assembly 588 when the sled 548A is properly insertedinto a drive bay. The second plug interface 648 comprises a second powerplug 654A and a second data/control plug 654B for respectively engagingthe power plug and data/control plugs associated with the back surfaceof a drive. The conductors 650 comprise: (a) power conductors 656A thatconnect the first power plug 652A and the second power plug 654A; and(b) data/control conductors 656B that connect the first data/controlplug 652B and the second data/control plug 654B. For accommodating two,half height drives, the second plug interface 648 further comprises anadditional data/control plug 658 and an additional power plug (notshown) that passes through holes 659 of the housing 642. A

[0158] Also associated with the housing 642 is a fan 660 that is used tocool any drive located within the housing 612 by causing air to movefrom the interior space 616 of the housing 612 to the exterior of thehousing 61.2 via a grill 662. Further associated with the housing 642 isa handle 664 that facilitates insertion/removal of the sled 548Ainto/from a drive bay.

[0159] By way of example, use of the drive bay assembly 540 comprisesmechanically associating a drive with a sled 548 by using screws toattach the drive to the housing 612 and electrically associating thedrive with the sled 548 using the second plug interface 648. Once thedrive has been mechanically and electrically associated with the sled548A, the drive can be associated with the library 202 by inserting thesled 548A into one of the drive bays 552A-552D and dissociated from thelibrary 202 by removing the sled 548A from the drive bay.

[0160] The drive bay assembly 540 further comprises a QIP 668 that ishoused in the QIP bay 554 and operates to distribute power, controlsignals and data to each of the drive bays 552A-552D. The QIP 668comprises a back panel 670 with a handle 672 that facilitatesinsertion/extraction of the QIP 668 into/from the QIP bay 554.

[0161] It should be appreciated that the drive bay assembly suitable 540is susceptible to numerous modifications. The following sets forth, withlimitation, some possible modifications. For instance, a drive bayassembly is feasible in which the drive bay housing is not susceptibleto being readily mounted and demounted from the frame of a library.Further, a drive bay assembly is feasible that has a different number ofdrive bays. Additionally, a drive bay assembly that is adapted to holdone or more drives in an orientation other than a horizontal orientationis feasible. Further, a drive bay that accommodates different types ofdrives, such as disk drive, is also practicable. A drive bay without aQIP bay and/or QIP is likewise feasible. Further, it should also beappreciated that a drive bay assembly is not required for a functionalmagazine-based data cartridge library.

[0162] Generally, the power supply system 216 provides DC power to thedrives 210 using a flat conductor that has a substantially rectangularcross-section, rather than a conventional conductor that has circularcross-section. The use of a flat conductor allows the space within alibrary to be more efficiently used or used to accommodate morecartridges and/or more drives.

[0163] With reference to FIGS. 27A-27D, the power supply system 216comprises a power supply 217 comprised of a box-like housing structurewith a top side 676A, bottom side 676B, front side 676C, back side 676D,first side 676E, and second side 676F. Associated with the front side676C are seven power supply bays 678 that each are capable ofaccommodating a sub-power supply. Generally, the power supply 217includes a sub-power supply in one of the bays for providing DC power toelements in the library 202 other than the drives 210. The six otherbays are populated with sub-power supplies depending on the number ofdrive bay assemblies that are attached to the ladder frame 542.Generally, one sub-power supply is required for each drive bay assemblyattached to the ladder frame 542. Also associated with the front side676C of the power supply 217 is a pair of AC receptacles 680, with eachreceptacle capable of accommodating an AC plug through which AC power isprovided to the power supply 216 for conversion to DC power. Alsoassociated with the front side 676C is a set of breakers 282 thatoperate to sever the connection with the source of AC power when thepower supply 216 is in an undesirable operating state, such as when thepower supply 216 is drawing too much current from the AC source. Thefirst side wall comprises a slot for accommodating an embodiment of aflat electrical power conductor 686 that has a first flat exterior face686A and a second flat exterior face 686B that extends substantiallyparallel to the first flat exterior face 686B.

[0164] The flat, electrical power conductor 686 extends vertically andadjacent to one side of the ladder frame 542. In the illustratedembodiment, only one vertical standard 688 of the ladder frame 542 isshown. The flat, electrical power conductor 686 is supported by achannel member 690, which is attached to the ladder frame 542. Thechannel member 690, in addition to supporting the flat, electrical powerconductor 686, also supports six power plugs 692A-292F, one plug foreach of the compartments 544A-544F of the ladder frame 542. Eachcompartment 544A-544F of the ladder frame 542 is capable ofaccommodating a drive bay assembly that, in turn, is capable ofaccommodating up to four full height drives and up to eight half-heightdrives.

[0165] The flat, electrical power conductor 686 is attached to thechannel member 690 using a plurality of hole hangers 694 that areattached to the conductor 686 and that each fit over a stud 696extending from the channel member. The electrical connection between theflat, electrical power conductor 686 and each of the plugs 692A-692F isachieved with taps 698A-698D that are each connected to one of theplanar electrical conductors 686 comprising the flat, electrical powerconductor 686. To elaborate, any of the drives that can be associatedwith a drive bay assembly and the QIP associated with a drive bayassembly presently require a +5V signal, a +12V signal, and two groundpaths (one for each of the voltage signals). Consequently, the flat,electrical power conductor 686 is a laminate of four electricalconductors, one for each of the two voltage signals and one for each ofthe two ground paths. If the library is modified so that differentelectrical signals are required, the flat, electrical power conductor686 can be modified accordingly.

[0166] As shown in FIG. 27E, an electrical power connection isestablished between the flat, electrical power conductor 686 and a drivebay assembly 700 in compartment 544F using a plug 702 that is associatedwith the QIP of the drive bay assembly 700 and that mates with the plug692F. An electrical connection is established between the flat,electrical conductor 686 and the power supply 216 by a tap assembly 704that extends between the conductor 686 and the points in the powersupply that provide the necessary voltage signals and ground paths. Itshould be appreciated that the tap assembly 704 comprises a horizontallyextending flat power conductor.

[0167] The distance between the first and second flat external faces686A, 686B of the flat, electrical power conductor 686 is approximately0.32 inches. In contrast, if a conventional round cable or bundled groupof round cables were designed to be able to provide power to the sametwenty-four drives 210, the cable or group of cables would have across-sectional measurement on the order of 3-4 inches.

[0168] It should be appreciated that the substantially rectangularcross-section shape of the flat, electrical power conductor 686 iscomplementary to the shapes of most of the other elements in the library202. As a consequence, the flat, electrical power conductor 686facilitates the layout of the library 202. In this regard, the flatsurfaces 686A, 686B are located so as extend substantially parallel orperpendicular to many of the surfaces associated with elements residingin the library. For instance, the flat surfaces 686A, 686B extendsubstantially parallel or perpendicular to the exterior surfaces of thehousing of the drive bay assembly 700. A horizontally extending flat,electrical power conductor, should one be needed, is also likely tofacilitate the layout of a library.

[0169] It should also be appreciated that the flat, electrical powerconductor 686 provides benefits in addition to spatial and/or layoutrelated benefits. Namely, the power conductor 686 has a largecapacitance that allows power to be provided to the drives in a highlyresponsive manner. Further, the electrical power conductor 686 producesless electrical “noise” than the prior approach. In addition, relativeto the prior approach, the electrical power conductor 686 allows fewerconnectors or plugs to be utilized. The use of fewer connectors or plugsis likely to relate to the production of less noise relative to theprior approach. It should be further appreciated that a flat, electricalpower conductor can also be applied to a cartridge-based library.

[0170] With reference to FIGS. 7B and 23C, the user definable space 336is a space in which the operator of the library 202 has a choice as tothe identity of the functional element or elements of the library thatoccupies all or a portion of the space.

[0171] The extent of the user definable space 336 of the library 202 islargely defined by the ladder frame 542. To elaborate, the userdefinable space 336: (a) extends vertically from approximately the topside 676A of the power supply 216 (which is located immediately underthe lower-most compartment of the ladder frame 542, namely, compartment544A) to the bottom side of cross-member 708; and (b) extends laterallybetween first and second sides 710A, 710B of the ladder frame 542. Withreference to FIG. 16, the depth of the user definable space 336 extendsfrom plane 330B to a substantially parallel plane located adjacent tothe back surface 340B of the library 202. Further, the ladder frame 542substantially divides the user-definable space 336 into six, equallysized spaces, namely, the compartments 544A-544F.

[0172] As previously noted, each of the compartments 544A-544F iscapable of accommodating one of the drive bay assembly 540. Moreover,the ladder frame 542 and the first and second mounting flanges 556, 560facilitate the mounting and demounting of the drive bay assembly 540from any one of the compartments 544A-544F. To reiterate, mounting ofthe drive bay assembly 540 in one of the compartments 544A-544F isaccomplished by aligning: (a) the first pair of notches 558A, 558Bassociated with the first mounting flange 556 of the drive bay assembly540 and the first pair of threaded holes 556A, 556B associated with aselected one of the compartments 544A-544F; and (b) the second pair ofnotches 562A, 562B associated with the second mounting flange 560 of thedrive bay assembly 540 and the second pair of threaded holes 566A, 566Bassociated with the selected one of the compartments 544A-544F. Once thenotches are aligned, bolts or screws are then used to secure the drivebay assembly 540 to the ladder frame 542. Demounting of the drive bayassembly 540 from the ladder frame 542 is accomplished by first removingthe bolts or screws, and then removing the drive bay assembly 540 fromthe ladder frame 542.

[0173] With reference to FIGS. 28A-28B, each of the compartments544A-544F is also capable of accommodating a magazine bay assembly 714that provides two shelves that are each capable of accommodating twomagazines. The magazine bay assembly 714 comprises a housing with a topwall 716A, a bottom wall 716B, a first side wall 716C, a second sidewall 716D, and a back wall 716E that define an interior space 718 forholding up to four magazines. The top wall 716A, bottom wall 716B, firstside wall 716C and second side wall 716D also define an opening 720through which any magazines can be inserted into and removed from theinterior space 718.

[0174] The magazine bay assembly 714 further comprises a first mountingflange 722 with a first pair of notches 724A, 724B, and a secondmounting flange 726 with a second pair of notches 728A, 728B. Mountingof the magazine bay assembly 714 to the ladder frame 542 and demountingthe magazine bay assembly 714 from the ladder frame 542 are done insubstantially the same manner as the drive bay assembly 540 is mountedand demounted from the ladder frame 542. Consequently, the mounting anddemounting of the magazine bay assembly 714 is not described further.

[0175] The magazine bay assembly 714 further comprises a first shelf 730capable of accommodating up to two magazines. The first shelf 730 isformed from the bottom wall 716B and three cleats 732A-732C that areeach substantially identical to the previously described cleat 522A. Themagazine bay assembly 714 further comprises a second shelf 734 that isalso capable of accommodating up to two magazines. The second shelf 734is formed from: (a) a planar member 736 that extends between and isattached to the first and second side walls 716C, 716D; and (b) threecleats 738A-738C, that are each substantially identical to thepreviously described cleat 522A. The operation of each of the first andsecond shelves 730, 734 is substantially identical to the operation ofthe previously described shelf 518. Consequently, the operation of theshelves 730, 734 is not described. It should, however, be noted thatlocated between the back wall 716E and the cleats 732A-732C is a biaselement 740 that applies a force to the cleats that prevents the cleatsfrom coming out of the holes that receive the cleats in the bottom wall.A bias element 742 performs the same function with respect to cleats738A-738C. Such bias elements are also present in the fixed shelving inthe library and perform the same bias function.

[0176] Based on the foregoing, a user or operator is able to choosewhether a drive bay assembly 540 or a magazine bay assembly 714 residesin each of the compartments 544A-544F associated wit the user-definablespace 336. Moreover, altering a choice is, due to the mountingstructures employed, relatively easy.

[0177] It should be appreciated that: (a) the user-definable space 336is a fixed space; (b) the compartments 554A-F each have a fixed size, afixed location and substantially the same size as the othercompartments; and (c) the drive bay assembly 540 and the magazine bayassembly 714 are also of substantially of the same size. A number ofmodifications to the user-definable space 336 or alternative embodimentsare feasible. Among the possible modifications or alternativeembodiments are, without limitation, a user definable space that has analterable size; compartments of varying number, location, and/or size;and/or assemblies for placing in the space that are of different sizesare feasible. Further, other mounting structures are feasible. Forexample, a ladder frame or similar structure with a mounting structurethat provides a high degree of flexibility as to the location that amodule is mounted is feasible.

[0178] Generally, a magazine transport is comprised of: (a) a magazinepicker that operates to move a magazine to and from a magazine storagelocation in the library; and (b) an elevator that operates to move themagazine picker adjacent to the locations in the library at whichmagazines can be stored. It should be appreciated that the locations ina magazine-based library at which magazines can be stored include: (a) afixed shelf or shelves; (b) an entry/exit port; and (c) a pass-throughport. Further, in certain embodiments, the elevator also positions themagazine picker adjacent to the drive or drives in the library.

[0179] With reference to FIGS. 29A-29H, the magazine transport 212comprises an elevator 750 for moving a magazine picker along horizontaland vertical axes so that the magazine picker can be positioned adjacentto the entry/exit port 206, any shelf of the shelf system 208, and anyof the drives 210. In this regard, the elevator 750 comprises: (a) avertical axis assembly 752 for moving a magazine picker verticallywithin the library 202, and (b) a horizontal axis assembly 754 formoving the magazine picker horizontally within the library. The verticalaxis assembly 752 supports or carries the magazine picker and generallyextends from a first end 756A to a second end 756B.

[0180] Generally, the horizontal axis assembly 754 supports the firstand second ends 756A, 756B of the vertical axis assembly 752 and iscapable of applying a horizontal driving force to each of the first andsecond ends 756A, 756B to horizontally displace the vertical axisassembly 752 within the library 202. In this regard, the horizontal axisassembly 754 comprises: (a) top assembly 758A for supporting andapplying a horizontal force to the first end 756A of the vertical axisassembly 752; (b) a bottom assembly 758B for supporting and applying ahorizontal force to the second end 756B of the vertical axis assembly752; and (c) a coordination assembly 758C for coordinating theapplication of horizontal forces to the first and second ends 756A, 756Bof the vertical axis assembly 752 by the top assembly 758A and thebottom assembly 758B.

[0181] With reference to FIG. 29B, the top assembly 758A comprises aU-shaped channel 760 with a first side 762A, second side 762B and thirdside 762C. The first side 762A is operatively attached to the interiorside of the top surface 340E of the frame. The second side 762B servesas a guide for a set of rollers associated with the first end 756A ofthe vertical axis assembly 752. In addition, the second side 762B alsosupports a pair of horizontal stops 764A, 764B that cooperate with astop block that is associated with the first end 756A of the verticalaxis assembly 752 to limit the horizontal extent over which thehorizontal axis assembly 754 can move the vertical axis assembly 752.The third side 762C supports a first pulley block 766A and associatedpulley 766B. In addition, the third side supports a second pulley block768A and associated pulleys 768B, 768C. Extending between the pulley766B and the pulley 768B is a belt 770. Associated with the belt 770 isa mount 772 for connecting the belt 700 to the first end 756A of thevertical axis assembly 752. The mount 772 also incorporates a structurethat allows the tension of the belt 770 to be adjusted. The pulley 768Cis associated with another belt that is used to: (a) transmit the forcesthat are used to horizontally displace the first end 756A of thevertical axis assembly 752 via the belt 770 and mount 772; and (b)coordinate the operation of the top assembly 758A with the bottomassembly 758B.

[0182] With reference to FIG. 29C, the bottom assembly 758B comprises aU-shaped channel 776 with a first side 778A, second side 778B and thirdside 778C. The first side 778A is operatively attached to the interiorside of the bottom surface 340F of the frame and supports a guide shaft780 that receives a linear bearing associated with the second end 756Bof the vertical axis assembly 752. The guide shaft 780 is supported by aset of stand-offs 782 that are operatively connected to the first side778A. The guide shaft 780 also comprises a pair of guide stops thatlimit the horizontal extent over which the horizontal axis assembly 754can move the vertical axis assembly 752. The first side 778A alsosupport a home position sensor 786 that detects when the vertical axisassembly 752 is positioned adjacent to the end of the guide shaft 780.The third side 778C supports a first pulley block 788A and associatedpulley 788B. In addition, the third side supports a second pulley block790A and associated pulleys 790B, 790C. Extending between the pulley788B and the pulley 790B is a belt 792. Associated with the belt 792 isa mount 794 for connecting the belt 792 to the second end 756B of thevertical axis assembly 752. The mount 794 also incorporates a structurethat allows the tension of the belt 770 to be adjusted. The pulley 790Cis associated with another belt that is used to: (a) transmit the forcesthat are used to horizontally displace first end 756A of the verticalaxis assembly 752 via the belt 770 and mount 772; and (b) coordinate theoperation of the top assembly 758A with the bottom assembly 758B.

[0183] With reference to FIGS. 29A-29C, the coordinating assembly 758Ccomprises the pulley 768C associated with the top assembly 758A, thepulley 790C associated with the bottom assembly 758, and a belt 798 thatextends between the pulley 768C and the pulley 790C. As can beappreciated, the coordinating assembly 758C interfaces with the topassembly 758A and the bottom assembly 758B so that movements of themount 772 associated with the top assembly 758A and the mount 794associated with the bottom assembly 758C are mirrored. As a consequence,when the first and second ends 756A, 756B of the vertical axis assembly752 are respectively attached to the mounts 772, 790 and a motive forceis applied to the mounts, the first and second ends 756A, 756B aredisplaced in the same manner. It should also be noted that the belt 798is enclosed within a housing 800.

[0184] Also associated with the bottom assembly 758B are a DC electricalmotor 802 and associated motor controller 804 that are used to providethe motive force for horizontally displacing the vertical axis assembly.To elaborate, any rotational force produced by the electrical motor 802is transmitted by a motor drive pulley system 806 comprised of a pulley(not shown) that is connected to the electrical motor 802, a drivepulley 808, and a belt 810 extending between the pulleys. The drivepulley 808 resides on the same axle (not shown) that the pulley 790C and790B reside. Consequently, rotation of the drive pulley 808 produces acorresponding rotation of the pulleys 790B, 790C. Rotation of the pulley790B causes the mount 794 to be horizontally displaced. Similarly,rotation of the pulley 790C ultimately causes the mount 772 to behorizontally displaced in a manner that mirrors the horizontaldisplacement of the mount 794. The home position sensor 786 is used inconjunction with an encoder associated with the electrical motor 802 orother position sensor known in the art to determine the horizontallocation of the vertical axis assembly 752.

[0185] With reference to FIG. 29D-29H, the vertical axis assembly 752generally comprises: (a) structures that interface the vertical axisassembly 752 with the top and bottom assemblies 758A, 758B; (b) a railstructure that supports a carriage that holds the magazine picker anddefines the vertical extent through which the carriage and associatedmagazine picker can be displaced; and (c) an actuation system thatprovides the motive force for vertically displacing the carriage alongthe rail structure.

[0186] With the foregoing general description in mind, the vertical axisassembly 752 comprises a first pair of guide roller bearings 816A, 816Band a second pair of guide roller bearing 818A, 818B for interfacing thevertical axis assembly 752 with the top assembly 758A of the horizontalaxis assembly 752. More specifically, the second side 762B of theU-shaped channel 760 associated with the top assembly 758A is receivedbetween the first pair of guide roller bearing 816A, 816B and betweenthe second pair of of guide roller bearings 816A, 816B to interface thevertical axis assembly 752 with the top assembly 758A of the horizontalaxis assembly 752. A stop block 820 located adjacent to the rollerbearings cooperates with the horizontal stops 764A, 764B of the topassembly 758A to limit the horizontal displacement of the vertical axisassembly 752. The vertical axis assembly 752 further comprises a linearbearing assembly 822 that receives the guide shaft 780 to interface thevertical axis assembly 752 to the bottom assembly 758B of the horizontalaxis assembly 752.

[0187] The vertical axis assembly 752 further comprises a rail mount 824that holds a linear rail 826 that can be displaced along the length ofthe rail mount 824. An upper rail stop 828 defines the upper limit alongthe rail mount 824 that the linear rail 826 can be displaced. The linearbearing assembly 822 defines the lower limit along the rail mount 824that the linear rail 826 can be displaced. Associated with the linearrail 826 is a pair of carriage blocks 830A, 830B that provide aninterface for a carriage bracket that connects the linear rail 826 tothe actuation system and to the carriage that supports the magazinepicker.

[0188] The vertical axis assembly 752 further comprises a pulley system832 is used to vertically displace the linear rail 826 along the railmount 826. The system 832 comprises a housing 834 that supports an upperpulley 836 and a lower pulley 838. Extending between the upper pulley836 and the lower pulley 838 is a belt 840. Associated with the belt 840is a mount 842 for connecting the belt 780 to the carriage bracket thatis, in turn, connected to the carriage blocks 830A, 830B associated withthe linear rail 826. The mount 842 also comprises a structure fortensioning the belt 780.

[0189] The vertical axis assembly 752 further comprises a DC electricmotor 844 and motor controller 846 for providing the motive force formoving the linear rail 826 along the rail mount 826. To elaborate, anyrotation force produced by the DC electric motor 844 is transmitted tothe lower pulley 838 of the pulley system 832 by another pulley systemcomprised of a motor pulley 848, a drive pulley 850 that is attached tothe same axle as the lower pulley 838, and a belt 852 that extendsbetween the motor pulley 848 and the drive pulley 850. Rotation of thelower pulley 838, in turn, causes the linear rail 826 to be displacedalong the rail mount 826.

[0190] With reference to FIGS. 29G-29H, the vertical axis assembly 752further comprises a carriage bracket 854 that is used to: (a)mechanically connect the linear rail 826 and the belt 840; and (b)mechanically connects the linear rail 826 to a carriage that supportsthe magazine picker. To elaborate, the carriage bracket 854 is connectedto the linear rail 826 by screws (not shown) that pass through holes inthe carriage bracket 854 and engage threaded holes in the carriageblocks 830A, 830B, which are fixedly attached to the linear rail 826.The carriage bracket 854 is connected to the belt 840 by: (a) a firstpair of pins 856 that are associated with the mount 842 and pass througha pair of holes associated with the bracket; and (b) a second pair ofpins 858 that are associated with the mount 842 and pass through asingle slot 860 associated with the bracket. The slot allows the secondpair of pins 858 to move when the tensioning device associated with themount 842 is actuated and still maintain a connection with the bracket854.

[0191] The vertical axis assembly 752 also comprises a channel guide 860that holds a flex cable that is used to transmit signals between thecontrol system 218 and magazine picker (as well as any other elementsassociated with the magazine picker) as the magazine picker isvertically displaced.

[0192] Further comprising the vertical axis assembly 752 is a flag 864that interacts with the home position sensor 786 to indicate when thevertical axis assembly 752 is located adjacent to the end of the guideshaft 780. To elaborate, the flag 864 interrupts an optical signaloutput by the home position sensor 786 to indicate when the verticalaxis assembly is located adjacent to the end of the guide shaft 780.Other sensing schemes are feasible.

[0193] The vertical axis assembly 752 further comprises a brakemechanism 868 that operates to engage the belt 840 during a loss ofpower and thereby prevent the magazine picker from dropping to thebottom of the library and potentially being damaged or damaging othercomponents of the library 202. The brake mechanism 868 comprises aroller 870 and a solenoid actuated brake assembly 872 that includes abrake shoe 874. The brake mechanism 868 operates so that when power isremoved from the library, the solenoid actuated brake assembly 872causes the brake shoe 874 to move so that the belt 840 is pinchedbetween the brake shoe 874 and the roller 870, thereby preventingfurther movement of the belt 840. Conversely, when power is beingapplied to the library, the solenoid actuated brake mechanism 872operates to hold the brake shoe 874 away from the belt 840 so that thebelt 840 can be moved as needed for the operation of the library.

[0194] The vertical location of the carriage or related elements isprovided using an encoder associated with the DC motor 844 or otherposition sensors known in the art.

[0195] It should be appreciated that the elevating function within thelibrary 202 and other magazine-based data cartridge libraries can beaccomplished with a number of different elevator designs. For example, acounter-weight elevator is feasible.

[0196] With reference to FIGS. 30A-30G, the magazine transport 212comprises a magazine picker 880 for moving a magazine towards and awayfrom a magazine storage location once the picker 880 has been positionedadjacent to the storage location by the elevator 750. Generally, themagazine picker 880 comprises: (a) a magazine support for supporting amagazine during movement of the magazine towards and away from a storagelocation in the library; and (b) a magazine transport device for movinga magazine between the magazine support and a storage location in thelibrary 202.

[0197] Before describing the magazine picker 880, the structure forattaching the magazine picker to the vertical axis assembly 752 isdescribed. With reference to FIG. 30A, the magazine picker 880 isoperatively connected to a carriage 882 that is, in turn, connected tothe carriage bracket 854 associated with the vertical axis assembly 752.

[0198] The magazine picker 880 comprises a support structure 884 forsupporting a magazine during transport of the magazine towards and awayfrom a storage location in the library 202. The support structurecomprises: (a) a base plate 886; (b) four brackets 888A-888D mounted tothe base plate 886; (c) a pair of rail mounting plates 890A, 890B, withthe rail mounting plate 890A supported by the brackets 888A, 888B andthe rail mounting plate 890B supported by the brackets 888C, 888D; (d) apair of rails 892A, 892B, with the rail 892A being attached to the railmounting bracket 890A, and the rail 892B attached to the rail mountingbracket 890B. Each of the rails 892A, 892B comprises two grooves 894A,894B, one for accommodating rail 292A of a magazine and one foraccommodating rail 292B of a magazine. In library 202, the shelf system208 is configured so that all of the magazines stored in the libraryhave the same orientation. Consequently, only one of the grooves 894A,894B associated with each of the 892A, 892B is utilized. For example,groove 894A of rail 892A may be used to accommodate rail 292A of amagazine, and groove 894B of the rail 892A would not be utilized.Continuing with the example, groove 894B of rail 892B would accommodaterail 292B of a magazine, and groove 894A of the rail 892B would not beutilized. The rail mounting plates 890A, 890B and the rails 892A, 892Bform a guide during movements of a magazine to and from a storagelocation and a support for a magazine during transport of a magazine andduring movements of a magazine to and from a storage location.Receptacles 896A, 896B are respectively associated with the railmounting plates 890A, 890B and engage the detents 296A, 296B located onthe bottom side 278 of a magazine to inhibit undesired movement of amagazine, especially during transportation of a magazine from onestorage location to another storage location.

[0199] The magazine transport 212 comprises a magazine transport device900 for moving a magazine between the support formed by the railmounting plates 890A, 890B and the rails 892A, 892B and a storagelocation in the library 202. The magazine transport device 900comprises: (a) a magazine engagement device 902 that is capable ofselectively engaging a magazine and disengaging from a magazine; and (b)a displacement device 904 for moving the magazine engagement device 902.

[0200] The displacement device 904 comprises: (a) a linear rail 906; (b)a bearing block 908 that is mounted to the linear rail 906, capable ofmoving along the linear rail 906, and supports the magazine engagementdevice 902; (c) a lead screw 910 that is supported by bearingsassociated with the brackets 888C, 888D; (d) a lead screw nut 912 forapplying a motive force to the magazine engagement device 902 to movethe device to a desired location along the linear rail 906; (e) a DCmotor 914 that is supported by the bracket 888C and provides therotational motive force that causes the lead screw nut 912 to move alongthe lead screw 910; (f) a first gear 916 and a second gear 918 that areused to transfer the rotational force produced by the DC motor 914 tothe lead screw 910; and (g) a center position flag 920 that cooperateswith a detector that is associated with the magazine engagement device902 to indicate when the displacement device 902 has positioned themagazine engagement device 902 over the center of the linear rail 906.

[0201] As can be appreciated, when the magazine engagement device 902 isattached to the bearing block 908 and the lead screw nut 912 engages themagazine engagement device 902, the production of a rotational force bythe DC motor 914 causes the lead screw nut 912 to move along the leadscrew 910 and, as a consequence, the magazine engagement device 902 tomove along the linear rail 906. The location of the magazine engagementdevice 902 is determined using an encoder associated with the motor 914or other position sensing device known in the art.

[0202] Generally, the magazine engagement device 902 operates so as to“hook” a magazine by rotating a toggle plate with pins that are locatedso as to pass through one of the pair of engagement holes associatedwith a magazine. Disengagement or “un-hooking” of the magazine isaccomplished by counter-rotating the toggle plate.

[0203] With the foregoing general description in mind, the magazineengagement device 902 comprises a toggle base 924 that is mounted to thebearing block 908 and a drive block 926 with a hole for receiving a postassociated with the lead screw nut 912. The magazine engagement device902 further comprises: (a) a toggle plate 928 that is pivotally mountedto the toggle base 924 with a toggle axle 930; and (b) a toggle actuatorsystem 932 for rotating the toggle plate 928 so as to engage a magazineand disengage from a magazine. The toggle plate 928 has a first end 934and a second end 936 with the axis of rotation for the toggle plate 928located between the first and second ends. Associated with the first end934 is a first pair of engagement pins 938A, 938B for passing through apair of engagement holes associated with a magazine. Likewise, a secondpair of engagement pins 940A, 940B are associated with the second end936 and also serve to engage a magazine via a pair of engagement holesassociated with the magazine. Also associated wit the first end 934 is afirst sensor assembly 942 that operates to detect the engagement flagstructure associated with a pair of engagement holes. To elaborate, whenthe engagement pins 938A, 938B pass through the engagement holes of amagazine (i.e., when a magazine has been “hooked”), the sensor detectsthe engagement flag structure, thereby confirming that the magazine hasbeen captured. A second sensor assembly 944 is associated with thesecond end 936 of the toggle plate 928 and operates in substantially thesame manner as the first sensor assembly 942. In an alternativeembodiment, an optical sensor system is used to detect the presence orabsence of the exterior of the bottom side 278 of the magazine todetermine whether or not a magazine has been engaged. The optical sensorsystem comprises a beam producing element and a reflected beam detectingelement. If the magazine has been engaged, the beam produced by the beamproducing element is reflected by the exterior of the bottom side 278 ofthe magazine and detected by the detecting element. If the magazine hasnot been engaged, the beam produced by the beam producing element is notdetected by the detecting element. One optical sensing system isassociated with each of the first end 934 and second end 936 of thetoggle plate 928. Also associated with the toggle plate 928 is arotational position flag 946 that is used with a detector to indicatethe rotational position of the toggle plate 928.

[0204] The toggle actuator system 932 comprises: (a) a stepper motor 950that is attached to the toggle base 924; (b) a pinion 952 that isattached to the spindle of the motor 950; (c) a cluster gear 954 that isattached to attached to the toggle base 924 and has a first gear 956that engages the pinion 952 and a second gear 958; (d) a driven gear 960that engages the second gear 958; (e) an overdrive arm 962; (f) a firstspring assembly 964 for connecting the driven gear 960 and the overdrivearm 962; and (g) a second spring assembly 966 for connecting theoverdrive arm 962 and the toggle plate 928. In normal operation, thestepper motor 950 produces a rotation force for rotating one of thefirst and second ends 934, 936 into position to engage a magazine. Therotation force is transmitted to the toggle plate 928 by the pinion 952,cluster gear 954, driven gear 960, first spring assembly 964, overdrivearm 962 and the second spring assembly 964. If, however, the rotation ofthe toggle plate 928 is inhibited such that the toggle plate 928 cannotreach the desired rotational position, one of the spring assembliescomes into play to allow the toggle plate 928 to cease rotating beforethe desired rotational position is reached. By allowing the toggle plate928 to cease rotating damage to the motor 950 and engagement pins isavoided, as well as damage to whatever is inhibiting the rotation of thetoggle plate 928. For example, if the stepper motor 950 is applying aforce to produce a clockwise rotation of the toggle plate 928, as viewedfrom the stepper motor side of the engagement device 902, and anobstruction is causing a counter-clockwise force to be applied to thetoggle plate 928, the second spring assembly 966 elongates to permit thetoggle plate 928 to cease rotating. When the obstruction is no longerpresent, the energy stored in the elongated spring assembly 966 causesthe toggle plate 928 to rotate to the desired position. The first springassembly 964 operates in a similar fashion when an obstruction preventsrotation of the toggle plate 928 in the counter-clockwise direction.

[0205] Also attached to the toggle base 924 is a sensor block 970 thatincludes: (a) a first sensor assembly 972 for cooperating with thecenter position flag 920 to provide an indication as to when therotational axis of the toggle plate 928 is positioned over the center ofthe linear rail 906; and (b) a second sensor assembly 974 forcooperating with the rotational position flag 946 to provide a signalindicative of the rotational position of the toggle plate 928. Theelectrical signals produced at the sensor block 970 are conveyed to aplug 976 by a flex cable 978. The plug 976 extends through the carriage882 and receives a plug that is connected to a controller located on theopposite side of the carriage 882 from the magazine picker 880.

[0206] A first detector 982 is attached to bracket 888A and is used todetect, on one side of the magazine picker 880, the end surface 532 of acleat associated with a shelf storage location for a magazine and thereference flag 632 associated with a sled in a drive bay assembly 540located on the one side of the magazine picker 880. A second detector984 is attached to the bracket 888B and serves the same purpose as thefirst detector 982 but with respect to any cleats and/or reference flagslocated on the other side of the magazine picker 880.

[0207] With reference to FIGS. 31A-31L, the operation of the magazinepicker 880 is described with respect to the moving of a magazine 988from a first shelf 990 that is associated with the two columns ofshelving 528B to a second shelf 992 that is associated with the fivecolumns of shelving 528A is described. For clarity, the only elements ofthe magazine picker 880 that are substantively shown in the notedfigures are the base plate 886, rail mounting plate 890A, rail 892A, andthe magazine engagement device 904. Associated with the first shelf 990is a cleat 994 that is functionally equivalent to the cleat 522A thatwas previously discussed. Likewise, a cleat 996 is associated with thesecond shelf 992. The magazine 988 is shown in cross-section so that theinteraction of the magazine engagement device with the engagement holesof the magazine can be seen.

[0208]FIGS. 31A-31B illustrate a preferred idle state for the magazinepicker 880, namely, with the rotational axis of the toggle plate 928 ofthe magazine engagement device 902 disposed over the center of thelinear rail 906 and the toggle plate 928 in a neutral position. Beforedescribing the movement of the magazine 988, it should be appreciatedthat the elevator 750 has been used to position the magazine picker 880adjacent to the first shelf 990. In this regard, the detector 984 hasbeen used to produce a signal that is used to cause the elevator 750 toposition the magazine picker 880 so that the magazine picker can removethe magazine 988 from the first shelf 990.

[0209] With reference to FIG. 31C, movement of the magazine 988commences with the magazine displacement device 904 moving the magazineengagement device 902 from the idle state location illustrated in FIGS.31A-31B and in direction 1000A to a location sufficiently adjacent tothe magazine 988 for the magazine engagement device 902 to engage themagazine 988. Engagement of the magazine 988 by the magazine engagementdevice 902 is accomplished by rotating the toggle plate 928 such thatthe engagement pins 940A, 940B associated with the second end 936 of thetoggle plate 928 can pass through first engagement holes 1002 (e.g.,engagement holes 298A, 298B) of the magazine 988 to engage the magazine988. The engagement of the magazine 988 is confirmed by the interactionof the second sensor assembly 944 with the engagement flag structure(e.g., engagement flag structure 300) of the magazine. Alternatively,the optical sensor system that detects a signal reflected by theexterior of the bottom side 278 of the magazine is used to confirm theengagement.

[0210]FIG. 31D illustrates an “over travel” condition that may occur inthe course of using the magazine engagement device 902 to engage themagazine 988 as shown in FIG. 31C. In an “over travel” situation, themagazine displacement device 904 has moved the magazine engagementdevice 902 in the direction that is opposite to the direction in whichthe magazine is to be moved and has moved the magazine engagement device902 so far in this direction that the magazine engagement device 902cannot engage the magazine. In the illustrated case, the magazinedisplacement device 904 has moved the magazine engagement device 902 toofar in the direction 1000A for the magazine engagement device 902 toengage the magazine 988. As a consequence, when the toggle plate 928 isrotated, the engagement pins 940A, 940B contact the bottom surface 278of the magazine 933, rather than pass through the engagement holes 1002.In this situation, the spring assembly 964 allows the toggle plate 928to cease rotating, thereby preventing potential damage to at least thestepper motor 950 and the magazine 988.

[0211] It should be noted that it may be desirable to perform an “overtravel operation” so that the magazine engagement device 902 engages themagazine 988 is unlikely to require more that none try to engage themagazine. In an over travel operation, the magazine displacement device904 purposely moves the magazine engagement device 904 in a directionthat is opposite to the direction in which the magazine is to be movedand moves the magazine engagement device 904 so far in this directionthat the engagement pins of the magazine engagement device 902 cannotengage the magazine and instead, upon rotation of the toggle plate 928,contact the bottom surface 278 of the magazine. When the engagement pinsof the toggle plate 928 contact the bottom surface 278 of the magazine,one of the spring assemblies 964A, 964B allows the toggle plate 928 tocease rotating. Subsequently, when the magazine displacement device 904moves the magazine engagement device 904 in the direction that themagazine is to be moved and the engagement pins reach the engagementholes of the magazine, the energy stored in one of the spring assemblies964A, 964B causes the toggle plate 928 to rotate and the engagement pinsto enter the engagement holes of the magazine and thereby positivelyengage the magazine on the first try.

[0212] To illustrate the use of the over travel operation, assume themagazine 988 is positioned further in the direction 1000B than isillustrate in FIG. 31C for some reason. In such a situation, themagazine engagement device 902 may not be able to engage the magazine988 if the magazine engagement device 902 is operated in a manner thatassumes that the engagement holes are in the location illustrated inFIG. 31C. If the magazine 988 is not engaged or cannot be engaged withthe magazine engagement device 902 in this position, the magazineengagement device 902 will have to be repositioned and the engagementoperation repeated. If, on the other hand, an over travel operation isperformed so that the magazine engagement device 902 is positionedfurther in direction 1000A than is shown in FIG. 31C, the magazineengagement device 902 can then contact the bottom side 278 of themagazine 988 as shown in FIG. 31D. Once the magazine 988 is contacted inthis manner, movement of the magazine engagement device 902 in direction1000B (which is the direction in which the magazine is to be movedanyway) and the operation of the first spring assembly 964 will causethe engagement pins 940A, 940B to pass through the first engagementholes 1002 of the magazine 988, thereby engaging the magazine 988.

[0213] With reference to FIG. 31E, once the magazine 988 has beenengaged, the magazine displacement device 904 is used to pull themagazine engagement device 902 and the engaged magazine 988 in direction1000B and onto the support formed by the rail mounting plates 890A, 890Band into engagement with the rails 892A, 892B.

[0214] With reference to FIG. 31F, the magazine displacement device 904is unable to move far enough in the direction 1000B to move the engagedmagazine 988 either completely onto the support structure of themagazine picker 880 or completely off of the first shelf 990.Consequently, the following operations have occurred relative to thestate of the magazine picker 880 shown in FIG. 31E: (a) the toggle plate928 has been rotated in the counter-clockwise direction to disengage thetoggle pins 940A, 940B from the magazine 988; (b) after disengagement,the magazine displacement device 904 has been moved in direction 1000Aso as to position the magazine engagement device 902 to re-engage themagazine (an “over-travel operation” may be employed); and (c) thetoggle plate 928 has been rotated in the clock-wise direction so thatthe engagement pins 938A, 938B associated with the first end 934 of thetoggle plate 928 pass through the engagement holes 1002 to re-engage themagazine 988.

[0215] With reference to FIG. 31G, after re-engagement of the magazine988 by the magazine engagement device 902, the magazine displacementdevice 904 is used to push the magazine engagement device 902 and theengaged magazine 988 further in the direction 1000B. At this point, themagazine 988 is completely supported by the magazine picker 880 andcompletely removed from the first shelf 990.

[0216] At this point, it should be appreciated that: (a) the stepsassociated with moving the magazine 988 from the first shelf 988 to themagazine picker 880 are exemplary of the steps associated with moving amagazine from any shelf in the library or from the entry/exit port tothe magazine picker 880; (b) the movement of the magazine 988 from thefirst shelf 990 to the magazine picker 880 required two separatedisplacements that were separated from one another by an amount of timeassociated with the disengagement and re-engagement of the magazine; (c)with the magazine 988 fully supported by the magazine picker 880 andcompletely removed from the first shelf 990, the 750 can be used to movethe magazine picker 880 and the magazine 988 to other locations in thelibrary; and (d) the magazine 988 could be moved back onto the firstshelf 990 or any other shelf associated with the two columns of shelving528B.

[0217] With reference to FIGS. 31H-31I, the use of the magazine pickerto move the magazine 988 from the magazine picker 880 to the secondshelf 992 is described. It should be appreciated that the movement ofthe magazine 988 to any shelf of the shelf system 208 involves similaroperations to those described hereinafter. Relative to the state of themagazine picker 880 shown in FIG. 31G, the following operations haveoccurred: (a) the toggle plate 928 has been rotated counter-clockwise todisengage the magazine engage device 902 from the engagement holes 1002;(b) after disengagement, the magazine displacement device 904 has movedthe magazine engagement device 902 in the direction 1000A to positionthe magazine engagement device 902 for engaging the magazine 988; and(c) the toggle plate 928 has been rotated in a counter-clockwisedirection so that the engagement pins pass through engagement holes 1004(e.g., engagement holes 306A, 306B) and thereby engage the magazine 988.An “under travel operation” may be performed so that it is unlikely thatengagement of the magazine will require more than one attempt. In anunder travel operation, the magazine displacement device 904 purposelymoves the magazine engagement device 904 in a direction that is oppositeto the direction in which the magazine is to be moved and before themagazine engage device 904 is at a location at which the magazine can beengaged, rotates the toggle plate 928 so that the engagement pinscontact the bottom surface 278 of the magazine. When the engagement pinsof the toggle plate 928 contact the bottom surface 278 of the magazine,one of the spring assemblies 964A, 964B allows the toggle plate 928 tocease rotating. Subsequently, when the magazine displacement device 904moves the magazine engagement device 904 further in the direction thatis opposite to the direction in which the magazine is to be moved, theengagement pins reach the engagement holes of the magazine and theenergy stored in one of the spring assemblies 964A, 964B causes thetoggle plate 928 to rotate and the engagement pins to enter theengagement holes of the magazine and thereby positively engage themagazine on the first try.

[0218] With reference to FIG. 31J, the magazine displacement device 904is used to pull the magazine engagement device 904 and the engagedmagazine 988 in direction 100B. At this point, the magazine 988 issupported partially by the second shelf 992 and partially by themagazine picker 880.

[0219] With reference to FIG. 31K, the magazine displacement device 904is unable to move far enough in the direction 1000B to move the engagedmagazine 988 either completely off of the support structure of themagazine picker 880 or completely on to the second shelf 992.Consequently, the following operations have occurred relative to thestate of the magazine picker 880 shown in FIG. 31J: (a) the toggle plate928 has been rotated in the clockwise direction to disengage the togglepins 940A, 940B from the magazine 988; (b) after disengagement, themagazine displacement device 904 has been moved in direction 1000A so asto position the magazine engagement device 902 to re-engage the magazine(an “under-travel operation” may be employed); and (c) the toggle plate928 has been rotated in the clockwise direction so that the engagementpins 938A, 938B associated with the first end 934 of the toggle plate928 pass through the engagement holes 1002 to re-engage the magazine988.

[0220] With reference to FIG. 31L, the magazine displacement device 904has pushed the magazine engagement device 904 and the engaged magazine988 in direction 1000B so that the magazine 988 is completely supportedby the second shelf 992.

[0221] At this point, it should be appreciated that: (a) the stepsassociated with moving the magazine 988 from the magazine picker 880 tothe second shelf 992 are exemplary of the steps associated with moving amagazine from the magazine picker 880 to any shelf in the library or tothe entry/exit port; and (b) the movement of the magazine 988 from themagazine picker 880 to the second shelf 992 required two separatedisplacements that were separated from one another by an amount of timeassociated with the disengagement and re-engagement of the magazine.

[0222] At this point, the toggle plate 928 can be rotated in acounter-clockwise direction to disengage the magazine 988. After anydisengagement, the magazine displacement device 904 can then be used tomove the magazine engagement device 902 in direction 1000A and returnthe magazine engagement device 902 to the preferred idle position.

[0223] The foregoing has described the magazine transport device 212used in the library 202. It should, however, be appreciated that otherthe invention is not limited to the particular design of the elevator750. For example, an elevator that operates based on a counter-weightprinciple is also feasible. Further, the invention is not limited to thedesign of the magazine picker 880. For instance, a magazine engagementdevice that operates by grasping oppositely situated surfaces of amagazine between two members, with either one member moving towards theother member to grasp the magazine or each member moving towards theother member to grasp a magazine, is possible. A magazine engagementdevice that operates by linearly translating one or more engagement pinsto engage a magazine and disengage from a magazine is also feasible. Forexample, FIG. 32 illustrates a magazine engagement device 1008 that usesa linear actuator 1010 to displace a camming device 1012 that, in turn,causes engagement pins 1014A, 1014B to be linearly translated to engagea magazine and disengage from a magazine. Yet another approach is to usea conveyor belt to engage and move a magazine between a supportstructure and a shelf.

[0224] Generally, the cartridge transport operates to move a datacartridge between a magazine and a drive. With reference to FIGS.33A-33B, the cartridge transport 214 is comprised of: (a) a cartridgetransport unit 1050; (b) a horizontal transport unit 1052 forhorizontally displacing the cartridge transport unit 1050; and (c) theelevator 750.

[0225] With continuing reference to FIGS. 33A-33B, the horizontaltransport 1052 is attached to a transport chassis 1054 that is, in turn,attached to the vertical axis assembly 752 of the elevator 750. Thetransport chassis 1054, in this embodiment, is an integration of thecarriage 882, the base plate 886, and the brackets 888A-888D, previouslydescribed with respect to the magazine transport 212. It should also benoted that the rail 892A comprises a spring-loaded detent 1055 forengaging one of the notches 295A, 295B associated with a magazine tosecure a magazine on the transport chassis 1054. A second spring-loadeddetent (not shown) is associated with the rail 892B and is used toengage the other of the notches 295A, 295B associated with a magazine.

[0226] The horizontal transport unit 1052 comprises: (a) a linear rail1056 that is attached to the transport chassis 1054; (b) a rail block1058 that is mounted to the linear rail 1056, capable of moving alongthe linear rail 1056, and supports the cartridge transport unit 1050;(c) a pair of stop blocks 1060A, 1060B for limiting the range over whichthe rail block 1058 can move along the linear rail 1056; (d) a leadscrew 1062 that is supported by a pair of brackets 1064A, 1064B that areattached to the transport chassis 1054; (e) a lead screw nut 1066 forapplying a motive force to the cartridge transport unit 1050 to move theunit to a desired location along the linear rail 1056; (e) a DC motor1068 that provides the rotational motive force that causes the leadscrew nut 1066 to move along the lead screw 1062, and is supported bybracket 1070 that is attached to the transport chassis 1054; (f) apinion 1072 that is attached to the spindle of the DC motor 1068; and(g) first gear 1074 and a second gear 1076 that are used to transfer therotational force produced by the DC motor 1068 to the lead screw 1062.

[0227] With reference to FIGS. 33C-33D, the cartridge transport unit1050 comprises a carriage block 1080 that is attached to the rail block1058 and engages the lead screw nut 1066. As can be appreciated, uponthe application of a rotational motive force by the DC motor 1068, thelead screw nut 1066 is displaced along the lead 1062 and, as aconsequence, the cartridge transport unit 1050 is horizontally displacedalong the linear rail 1056. Horizontal displacement of the cartridgetransport unit 1050 along the linear rail 1056 facilitates: (a)positioning of the cartridge transport unit 1050 over a particular slotof a magazine supported by the magazine picker 880 so that a datacartridge can be inserted into the slot or a data cartridge can beextracted from the slot; and (b) moving the cartridge transport unit1050 towards and away a drive during the transfer of a data cartridgebetween a magazine and the drive. The location of the cartridgetransport unit 1050 is determined using an encoder associated with theDC motor 1068 or other position sensor known in the art.

[0228] With reference to FIGS. 33C-33F, the cartridge transport unit1050 further comprises: (a) a housing 1082 that defines an interiorspace 1084A for receiving a data cartridge and an opening 1084B throughwhich a cartridge is received into the interior space 1084A and throughwhich a cartridge is expelled from the interior space 1084A (sensor islocated adjacent to the opening 1084B for use in determining whether adata cartridge has been grasped and for determining whether a cartridgeis in a magazine); and (b) a rotary assembly 1086 for selectivelyrotating the housing 1082. The rotary assembly 1086 comprises: (a) abracket 1088 that is attached to the carriage block 1080; (b) a gear1090 with a center bearing 1092 for attaching the bracket 1088 to thegear so as to allow relative rotational movement between the bracket1088 and the gear, and with an outer gear ring 1094 that is fixed to thehousing 1082; (c) a DC motor 1096 for providing a rotational motiveforce that is used to rotate the housing 1082 about an axis defined bythe center bearing 1092, the DC motor 1096 is attached the housing 1082by a bracket 1098; (d) a pinion 1100 that is attached to the spindle ofthe DC motor 1096 and engages the outer gear ring 1094. As can beappreciated, a rotational motive force produced by the DC motor 1096 istransmitted to the outer gear ring 1094 by the pinion 1100. As aconsequence, the housing 1082 rotates relative to the carriage block1080 and about the axis 1096. A rotational sensor 1102 that is attachedto the housing 1082 cooperates with a flag 1104 that is associated withthe bracket 1088 to providing information on the rotational position ofthe housing 1082.

[0229] With reference to FIG. 34A, due to orientation of the drives 210and the orientation of a cartridge 1104 in a magazine 1106 supported bythe magazine picker 880, the rotary assembly 1086 must be able to rotatethe housing 1082 through a range 1108 of a least ninety degrees locatedbetween a vertical plane 1110 and a horizontal plane 1112 to transfer acartridge between one of the drives 210 and a magazine supported by themagazine picker 880. In the illustrated embodiment, the rotary assemblyis able to rotate the housing 1082 through an additional range 1114 ofabout forty-five degrees. The ability to traverse a total range ofapproximately 135 degrees allows a bar-code reader associated with thehousing 1082 to read bar codes associated with magazines located onshelves 328A and shelves 328B, i.e., magazines located on both sides ofthe magazine transport 212 and cartridge transport 214. The range of therotary assembly 1086 can be further increased if, for example, anadditional drive or drives were located on the opposite side of thelibrary from the drives 210.

[0230] The housing 1082 comprises a top side 1118A, bottom side 1118B,first side 1118C, second side 1118D, and back side 1118E. Associatedwith the back side 1118E is a bar code reader 1120 that is used to reada bar code label that is associated with and identifies a magazine thatis located on a shelf in the shelf system 208 and a bar label that isassociated with a data cartridge magazine located in a magazine. Thebarcode reader 1120 has an aperture 1122 with a field of view thatextends through the interior space 1084A of the housing 1082 and outthrough the opening 1084B defined by the housing 1082. FIG. 34Billustrates the ability of the rotary assembly 1086 and the bar codereader 1120 to read a bar code that identifies a first magazine 1124Athat is associated with the shelving 328A and a bar code that identifiesa second magazine 1124B that is associated with the shelving 328B. Withrespect to the magazines disclosed herein and the common orientation ofall of the magazines in the library 202, the bar code label associatedwith the magazine 1124A is situated in one of the recesses 290A, 290Band the bar code label associated with the magazine 1124B is situated inthe other of the recesses 290A, 290B. As FIG. 34B also illustrates, therotary assembly 1086 and the bar code reader 1120 are also capable ofreading a bar code label that is attached to an end face 1126 of acartridge. In some cases, the horizontal transport unit 1052 must alsobe used to appropriately position the bar code reader 1120 to read a barcode label associated with a magazine or with a cartridge. It should beappreciated that a bar code reader could be located in a differentlocation on the housing. Further, separate bar code readers can also beemployed, one to read a bar code that identifies a magazine and one toread a bar code that identifies a cartridge. If two bar code readers areemployed, the bar code reader reading the bar code that identifies amagazine can be located elsewhere than the cartridge transport unit 1050(e.g., with the magazine picker 880). Additionally, a reader or readerscan be employed that are not adapted to read bar codes are feasible. Forinstance, if an RFID tag is used to identify a magazine or cartridge, anappropriately situated reader or readers can be associated with thecartridge transport 214, magazine transport 212, or other appropriateelement in the library.

[0231] With reference to FIGS. 33E and 33G-331, the housing 1082 iscapable of accommodating data cartridges of different dimensions. Morespecifically, the housing 1082 is capable of accommodating cartridgesthat have different heights, i.e., the perpendicular distance betweenthe two, parallel surfaces of the cartridge with the greatest surfaceareas. In the illustrated embodiment, the housing 1082 is capable ofaccommodating an LTO, SAIT or DLT tape cartridge. LTO and SAIT tapecartridges have substantially the same height. The DLT tape cartridge,however, has a height that is greater than the heights of the LTO andSAIT tape cartridges. With the foregoing in mind, the housing 1082comprises a top half 1130A and a bottom half 1130B that is attached tothe top half 1130A to form the housing 1082. Adaptively attached to thetop half 1130A is plate 1132. To elaborate, the top half 1130Acomprises: (a) screw holes 1134A-1134D each for receiving a screw, suchas screw 1136; (b) spring towers 1138A-1138D that each house a spring.The plate 1132 comprises: (a) retaining screw posts 1140A-1140D thateach receive and retain a screw that passes through the correspondingone of the screw holes 1134A-1134D; and (b) spring seats 1142A-1142D,each for supporting one end of a spring, such as spring 1144. The otherend of each spring is received in the spring towers 1138A-1138D. Theplate 1132 also comprises a ramp 1146 that is disposed adjacent to theopening 1084B to facilitate the insertion of data cartridges into theinterior space 1084A. In operation, the plate 1132 and the interiorsurface of the bottom side 1118B are separated from one another whenthere is no cartridge in the interior space 1084A by a distance that isonly slightly greater than the height of an LTO or SAIT tape cartridge.When an LTO or SAIT tape cartridge is located in the interior space1084A, the plate 1132 and the interior surface of the bottom side 1118Bremain separated by approximately the same distance as when there was nocartridge in the interior space 1084A. In addition, the plate 1132 andinterior surface of the bottom side 1118B operate to constrain themovement of the cartridge in one dimension, i.e., the height dimension.When a DLT cartridge is inserted into the interior space 1084A, thegreater height of the cartridge displaces the plate 1132 towards the topside 1118A of the housing and compresses the springs. Again, the plate1132 and the interior surface of the bottom side 1118B constrain themovement of the cartridge in one dimension, i.e., the height dimension.When the DLT cartridge is removed from the interior space 1084A, thesprings operate to return the plate 1118B to the position at which it isseparated from the interior surface of the bottom side 1118B by adistance that is slightly greater than the height of an LTO or SAITcartridge.

[0232] The plate 1132 further comprises a flag 1148 that cooperates witha detector 1150 to indicates when a DLT tape cartridge has been receivedin the interior space 1084A. In operation, when a DLT cartridge isreceived in the interior space 1084A, the displacement of the plate 1132causes the flag 1148 to pass through a slot 1152 in the top half 1130Aand engage the detector 1150. The detector 1150 is located on a circuitboard 1154 that is mounted to the top side 1118A of the housing and thatincludes control circuitry for the rotary assembly 1086 and the picker.

[0233] With reference to FIGS. 33K-33N, the cartridge transport unit1050 comprises: (a) a grasper assembly 1160 that is used to grasp acartridge; and (b) a linear drive assembly 1162 for moving a portion ofthe grasper assembly 1160 to move a cartridge into and out of theinterior space 1084A of the housing 1082. The grasper assembly 1160comprises: (a) the plate 1132 and the interior surface of the bottomside 1118B of the housing 1082, which cooperate with one another toconstrain a data cartridge in a first dimension, i.e., the heightdimension; (b) a picker assembly 1164 and the interior surface of theback side 1118E of the housing 1082, which cooperate with one another toconstrain a cartridge in a second dimension, i.e., the depth dimensionbetween the ends of the cartridge; and (c) the interior surface of thefirst side 1118C of the housing in combination with an interior wall1166 of the housing 1082 and the picker assembly 1164 to constrain acartridge in a third dimension, i.e., the width dimension.

[0234] The picker assembly 1164 comprises: (a) a finger/thumb assembly1168 that is used in grasping a cartridge; and (b) a finger actuationassembly 1170 that is used to place a finger associated with thefinger/thumb assembly 1168 in a desired orientation for extracting adata cartridge from a magazine, inserting a data cartridge into amagazine, extracting a data cartridge from a drive, and inserting a datacartridge into a drive.

[0235] The linear drive assembly 1162 operates to linearly move thefinger/thumb assembly 1168 to pull a cartridge into the interior space1084A of the housing 1082 and to expel a cartridge from the interiorspace of the housing 1082. The linear drive assembly 1162 comprises: (a)a lead screw 1174 that is supported by the housing 1082; (b) a DC motor1176 for providing a rotational motive force for moving the finger/thumbassembly 1168, the motor is attached to a bracket 1178; (c) a pinion1180 that is attached to the spindle of the DC motor 1176; (d) an idlergear 1182 that interfaces with the pinion 1180; (e) a lead screw gear1184 that interfaces with the idler gear 1182 and is attached to one endof the lead screw 1174. The finger/thumb assembly 1168 comprises a nutportion 1188 that resides on the lead screw 1174 and a guide tongue 1190that is attached to the nut portion 1188 and resides in a groove 1192, aside of which is formed by the interior wall 1166. When the motor 1176produces a rotational motive force, the finger/thumb assembly 1168 isdisplaced along the lead screw 1174. Typically, the displacement isassociated with moving a cartridge into the interior space 1084A orexpelling a cartridge from the interior space 1084A. Associated with thefinger/thumb assembly 1168 is a flag 1194 that cooperates with adetector 1196 to indicate when the finger/thumb assembly 1168 has beenfully retracted into the interior space 1084A of the housing 1082. Inaddition, the detector 1196 is used in combination with an encoderassociated with the motor 1176 to provide positional information on thefinger/thumb assembly 1168.

[0236] The finger/thumb assembly 1168 further comprises: (a) mountingblock 1200; (b) a finger 1202 that is pivotally attached to the mountingblock 1200 via a finger pivot shaft 1204; (c) finger cam 1206 that isattached to the finger 1202 and includes a first and second finger camlegs 1208A, 1208B; (d) a finger return spring assembly 1210 that isattached to the pivot shaft 1204 and operates to bias the finger 1202towards a data cartridge; and a thumb 1212 that limits the movement ofthe finger 1202 towards a cartridge and also assists in pushing acartridge out of the interior space 1084A. It should be appreciated thatin embodiments of a magazine-based data cartridge library that operateonly on cartridges with two gripper notches, a cartridge may be graspedbetween a pair of movable elements.

[0237] The finger actuation assembly 1170 comprises: (a) a bracket 1216that is mounted to the housing 1082; (b) a picker 1218 that is pivotallyattached to the bracket 1216; (c) a picker cam 1220 that engages thefinger cam surface 1206 to place the finger 1202 in desired orientationsfor particular insertion and extraction operations, with the picker cam1220 comprising first and second picker cam legs 1222A, 1222B; (d) asolenoid 1224 that is used to rotate the picker 1218 and comprises aplunger 1226 that is attached to the picker 1218; and (e) a stop 1228that limits the rotation of the picker 1218 in one direction.

[0238] Also associated with the cartridge transport 214 is a wallstructure 1230 that serves to counteract the rotation of a cartridgethat occurs during extraction of the cartridge from a magazine orinsertion the cartridge into the magazine due to the manner in which thepicker assembly engages the cartridge.

[0239] It should also be appreciated that the cartridge transport 214and the magazine transport 212 both comprise the elevator 750. As aconsequence, elements of the cartridge transport 214 other than theelevator 750 and elements of the magazine transport 212 other than theelevator 750 are moved in unison by the elevator 750. This relationshipmakes possible bulk load and bulk unload operations. However, it shouldbe appreciated that in other embodiments a cartridge transport and amagazine transport can each have an elevator that is capable ofindependent operation. Further, the operational ranges of the elevatorscan be substantially the same or different. Further, a cartridgetransport with fewer actuators than those associated with the cartridgetransport 214 is feasible. For example, a cartridge transport withelements that are functionally equivalent to all of the elements of thecartridge transport 214 described above, except for the elevator, couldbe mounted adjacent to a drive. In such an embodiment, a magazinetransport would bring a magazine into the operational range of thecartridge transport for the loading of cartridges into the magazine bythe cartridge transport and the unloading of a cartridge from themagazine by the cartridge transport. In another possible embodiment, acartridge transport with elements that are functionally equivalent toall of the elements of the cartridge transport 214 described above,except the elevator 750 and the horizontal transport 1052, could bemounted adjacent to a drive. In such an embodiment, the magazinetransport would operate to bring magazines into the general operationalrange of the cartridge transport and the magazine picker would be usedto position a specific slot of a magazine for the loading and unloadingof cartridges by the cartridge transport. In any event, a cartridgetransport is a device that is capable of moving a data cartridge betweena magazine and a drive.

[0240] With reference to FIGS. 35A-35C, the operation of the cartridgetransport 214 in moving a data cartridge 1232 from a magazine 1234 to adrive 1236 is generally described. With reference to FIG. 35A, themagazine transport 212 has been used to move the magazine 1234 from astorage location, such as a shelf or the entry exit port, to the supportstructure 884. To elaborate, the magazine transport 212 has, ifnecessary, used the elevator 750 to position the magazine picker 880 andthe support structure 884 adjacent to the whatever storage location wassupporting the magazine 1234. In this regard, one of the detectors 982,984 was used to position the magazine picker 880 and the supportstructure 884. Further, the rotary assembly 1086 has likely been used toplace the housing 1082 and the associated bar-code reader 1120 at anorientation that allows the bar-code reader to read a bar-code labelassociated with the magazine 1234 to confirm that the appropriatemagazine is being accessed. Once the magazine picker 880 and supportstructure 884 were positioned adjacent to the storage location that wassupporting the magazine 1234, the magazine picker 880 and supportstructure 884 were used to move the magazine 1234 from the storagelocation to the support structure 884. During the moving of the magazine1234 onto the support structure 884, the rotary assembly 1086 has beenused to place housing 1082 and the associated bar-code reader 1120 at anorientation that allowed the bar code reader 1120 to read the bar-codelabels associated with the cartridges in the magazine 1234 to identifythe desired cartridge, namely, cartridge 1232. In this regard, therotary assembly 1086 is typically used to place the housing 1082 in thevertical orientation shown in FIG. 35A or at an angle that is betweenthe vertical and horizontal planes 1236A, 1236B so that the bar-codereader 1120 can read the bar-codes associated with cartridges in themagazine.

[0241] With reference to FIG. 35A, after the magazine 1234 has beenpositioned on the support structure 884 as shown in FIG. 35A or duringthe time when the magazine 1234 is being positioned on the supportstructure 884, the horizontal transport unit 1052 and the rotaryassembly 1086 are used, as needed, to position the opening 1084B of thehousing 1082 to receive the data cartridge 1232. The linear driveassembly 1162 and the picker assembly 1164 are then used to draw thecartridge 1232 into the interior space 1084A of the housing 1082. Thedetector 1196 is used to determine when the cartridge 1232 has beenfully retracted into the interior space 1084A of the housing 1082. Atthis point, it should be appreciated that: (a) the magazine 1234 hasoriented the cartridge 1232 (an LTO magazine) such that the face of thecartridge with the greatest surface area lies in a vertical plane; and(b) that in extracting the cartridge 1232 from the magazine 1234, thecartridge has been vertically displaced within the vertical plane.

[0242] At some point in retracting the cartridge 1232 into the housing1082, cartridge 1232 and elements of the cartridge transport 214 aresituated so as not to interfere with any movement of the magazine 1234.At this point, the magazine picker 880 can be used to transfer themagazine 1234 from the support structure 884 to its original storagelocation or to another storage location, which may require the use ofthe elevator 750. Alternatively, the magazine 1234 can be left on thesupport structure 884. Leaving the magazine 1234 on the supportstructure 884 is desirable if, for example, a “bulk load” operation isto be performed.

[0243] In any event, after the picker assembly 1164 has engaged thecartridge 1232, the rotary assembly 1086 is used to rotate the housing1082 and the grasped cartridge 1232 from the vertical orientation shownin FIG. 35A to the horizontal orientation shown in FIG. 35B. Typically,the rotary assembly 1086 rotates the housing 1082 after the cartridge1232 has been completely retracted into the housing 1082. However, incertain circumstances, it is possible for the rotary assembly 1086 torotate the housing 1082 during the period of time when the cartridge isbeing retracted into the housing. For cartridges located in the slots ator near the ends of the magazine, rotation of the housing 1082 to thehorizontal orientation shown in FIG. 35B may also require that thehorizontal transport unit 1052 horizontally and linearly translate thehousing 1082 towards the center of the magazine 1234 to prevent thehousing 1082 from coming into contact with a shelf or other element ofthe library. At this point, it should be appreciated that the cartridge1232 has been rotated about a horizontal axis and about a horizontalaxis that is parallel to the face of the cartridge 1232 with thegreatest surface area.

[0244] With reference to FIG. 35C, the horizontal transport unit 1052 isused, as needed, to linearly and horizontally translate the housing 1082and the cartridge 1232 in the direction required to insert the cartridge1232 into the drive 1236. In addition, the elevator 750 and detector 984(which operates in this instance to detect the flag 632 associated withthe drive 1236) have been used, as needed, to position the housing 1082so that when the housing 1082 is horizontally disposed as shown in FIGS.35B and 35C, the opening of the housing is aligned with the receptacleof the drive 1236. The elevator 750 and detector 984 can be used toposition the housing 1082 for insertion of the cartridge 1232 into thedrive 1236 at any time after the magazine 1234 has been loaded onto thesupport structure 1084. Once the opening 1084B of the housing 1082 hasbeen aligned with the receptacle of the drive 1236, the cartridge 1232is inserted into the drive 1236. In this regard, the linear driveassembly 1162 is used to expel the cartridge 1232 from the housing 1082and into the drive. The linear drive assembly 1162 typically beginsexpelling the cartridge after the opening 1084B has been disposedsubstantially adjacent to the receptacle of the drive 1236. However, theexpulsion process can commence earlier. However, there may be risksassociated with commencing the expulsion process earlier.

[0245] At this point, if the magazine 1234 is still associated with thesupport structure 884, a bulk load operation can be performed, ifdesired. In a bulk load operation, the housing 1082 is repositionedusing the horizontal transport unit 1052 and the rotary assembly 1056,as needed, so that a second cartridge in the magazine 1234 can begrasped. The second cartridge is grasped and then oriented for insertioninto a second drive in the same manner as previously described withrespect to the cartridge 1232. Further, the elevator 750 is used toposition the housing 1082 for insertion of the second cartridge into asecond drive. The process of grasping a cartridge in the magazine 1234,orienting the housing 1082 and the grasped cartridge using the rotaryassembly 1054 and horizontal transport unit 1052, as needed, forinsertion the grasped cartridge into a drive, and using the elevator 750to position the housing 1082 and the grasped cartridge for insertioninto a drive is repeated until the desired number of cartridges havebeen transferred from the magazine 1234 to the drives.

[0246] It should also be noted at this point that the process for movinga data cartridge from a magazine to a drive involved the use of themagazine picker 880 to move a magazine onto the support structure 884such that the magazine was no longer associated with a storage locationand completely supported by the support structure 884. If only onecartridge is to be moved from a magazine to a drive, an alternativeprocess potentially avoids the need to fully extract the magazine fromits storage location. In this process, the magazine picker terminatesthe extraction of a magazine from a storage location after the desiredcartridge has been exposed and is capable of being grasped. In oneembodiment, the horizontal transport unit 1052 is used to position thehousing 1082 as close to the storage location from which the magazine isto be extracted as is feasible. Further, the rotary assembly 1086 placesthe housing 1082 in the vertical orientation shown in FIG. 35B. With thehousing 1082 positioned by the horizontal transport unit 1052 and therotary assembly 1086 in this manner, the desired cartridge can begrasped very quickly once it is exposed. To elaborate, the signalprovided by the bar-code reader 1120 once the desired cartridge isexposed and detected is used to terminate the operation of the magazinepicker 880 such that the desired cartridge is positioned underneath theopening 1084B of the housing 1082. It should be appreciated that if theslot in which the desired cartridge is located is known beforehand, thisinformation can be used to terminate the operation of the magazinepicker 880 such that the desired cartridge is positioned underneath theopening 1084B of the housing 1082. In any event, extraction of thecartridge from the magazine proceeds as previously described. However,if the magazine has not been completely extracted from its storagelocation, a decision must be made as to whether to proceed with theextraction of the magazine from its storage location or proceed toreinsert the magazine into its storage location because the elevator 750cannot be used to move the grasped cartridge to a drive until themagazine is substantially removed from its storage location orsubstantially inserted into its storage location. In either case, oncethe magazine has been substantially removed from its storage location orsubstantially returned to its storage location, the grasped cartridge ismoved to a drive as previously described.

[0247] The operation of the cartridge transport 214 in moving a datacartridge 1232 from a drive 1236 to a magazine is generally describedwith reference to FIGS. 35A-35C. With reference to FIG. 35C, theelevator 750 and the detector 984 have been used to grossly position thehousing 1082 adjacent to the drive 1236, which holds the cartridge 1232.Further, the horizontal transport unit 1052 and the rotary assembly 1086have been used, as needed, to orient the housing 1082 as shown in FIG.35C. Consequently, through the operation of the elevator 750, horizontaltransport 1052 and the rotary assembly 1086, as needed, the housing 1082has been positioned to receive the cartridge 1232 from the drive 1236.Although FIG. 35C shows the magazine 1234 on the support structure 884,the magazine 1234 may or may not be associated with the supportstructure 884 when the housing 1082 is positioned to receive thecartridge 1232 from the drive 1236. If the magazine 1234 is associatedwith the support structure 884, a “bulk unload” operation can beperformed, if desired. In any event, the linear drive assembly 1162 andpicker assembly 1164 operate to extract the cartridge 1232 from thedrive 1236.

[0248] With reference to FIGS. 35B and 35C, once the cartridge 1232 issubstantially clear of the drive 1236, the horizontal transport unit1052 (as needed) and the rotary assembly 1086 are used to position thehousing 1082 and the grasped cartridge 1232 for insertion into themagazine 1234. Even though the housing 1082 and the grasped cartridge1232 are being position for insertion of the cartridge into themagazine, it should be appreciated that the magazine may or may not beassociated with the support structure 1084 during this positioning ofthe housing 1082 and the grasped cartridge. At this point, it should beappreciated that the cartridge 1232 has been rotated about a horizontalaxis and about a horizontal axis that is parallel to the face of thecartridge 1232 with the greatest surface area. After the cartridge 1232is substantially clear of the drive 1236, the elevator 750 and one ofthe detectors 982, 984 is used to position the magazine picker 880 andthe support structure 884 adjacent to the storage location of themagazine 1234.

[0249] After the housing 1082 and the grasped cartridge 1232 have beenpositioned as shown in FIG. 35A, the cartridge is positioned forinsertion into the magazine 1234. Although FIG. 35A shows the magazine1234 as being on the support structure 884, the magazine 1234 may notyet be associated with the support structure. In any event, beforeinsertion of the cartridge 1232 into the magazine 1236 can beaccomplished, the magazine 1234 is positioned on the support structure884 as shown in FIG. 35A. If the magazine 1234 was not associated withthe support structure 884 when the housing 1082 was positioned toreceive the cartridge 1232 from the drive 1236, the magazine 1234 isextracted from its storage location after the elevator 750 hasappropriately positioned the support structure 884 adjacent to thestorage location of the magazine 1234. Once the housing 1082 and graspedcartridge 1232 and the magazine 1234 are positioned as shown in FIG.35A, the linear drive assembly 1162 and the picker assembly 1164 operateto expel the cartridge from the housing 1082 into the magazine 1234. Itshould be noted at this point that in inserting the cartridge 1232 intothe magazine 1234: (a) the cartridge was oriented such that the face ofthe cartridge with the greatest surface area lay in a vertical plane;and (b) that the cartridge 1232 was vertically displaced within thevertical plane.

[0250] It should be noted that if the magazine 1234 was associated withthe support structure 884 when the housing 1082 was positioned toreceive the cartridge 1232 from the drive 1236, a “bulk unload”operation can be performed in which the cartridge 1232 is returned tothe magazine 1234 as described except that before the elevator 750 andmagazine picker 880 are used to return the magazine 1234 to its storagelocation, the elevator 750, horizontal transport uniti 1052, rotaryassembly 1086 and grasper assembly 1160 are used to move additionalcartridges from other drives to the magazine 1234.

[0251] It should also be noted that in the situation in which themagazine is not associated with the support structure 884 when thehousing 1082 is positioned to receive the cartridge from a drive, aprocess in which a cartridge can be returned to a magazine in many caseswithout fully extracting the magazine from its storage location can beimplemented. To elaborate, the if the magazine 1234 was not associatedwith the support structure 884 when the housing 1082 was positioned toreceive the cartridge 1232, the magazine 1234 must be extracted from itsstorage location after the cartridge 1234 has been extracted from thedrive and the elevator 750 has positioned the support structure 884adjacent to the storage location for the magazine 1234. In this process,the magazine picker terminates the extraction of a magazine from astorage location after the desired cartridge has been exposed and iscapable of being grasped. In one embodiment of the process, the magazinepicker 880 terminates the extraction of a magazine from its storagelocation after the slot that is to store the cartridge has been exposed.In one embodiment, the horizontal transport unit 1052 is used toposition the housing 1082 as close to the storage location from whichthe magazine is to be extracted as is feasible. Further, the rotaryassembly 1086 places the housing 1082 in the vertical orientation shownin FIG. 35B. With the housing 1082 positioned by the horizontaltransport unit 1052 and the rotary assembly 1086 in this manner, thecartridge can be inserted into the magazine shortly after the slot thatis to retain the cartridge is exposed. To elaborate, signals provided bythe operation of the center position flag 920 in conjunction with thefirst sensor assembly 942 and an encoder associated with the motor 914are used to determine when the slot in which the magazine is to beplaced is exposed and uses these signals to terminate the operation ofthe magazine picker 880 such that the desired cartridge is positionedunderneath the opening 1084B of the housing 1082. At this point, thelinear drive assembly 1162 and the picker assembly 1164 operate toinsert the cartridge into the magazine. Once the cartridge issufficiently inserted into the magazine, the magazine picker 880operates to return the magazine to its storage location.

[0252] It should also be appreciated that the magazine from which acartridge is extracted does not have to be the magazine to which thecartridge is later returned.

[0253] If desired, the cartridge transport 214 can also be used to movea cartridge from one drive to another drive. To move a cartridge fromone drive to another drive, the elevator 750, horizontal transport unit1052, and rotary assembly 1086 are used to position the housing 1082 asshown in FIG. 35C to receive a data cartridge from the drive 1236. Oncethe housing 1082 has been positioned to receive a data cartridge fromthe drive, the linear drive assembly 1162 and the picker assembly 1164are used to extract the cartridge from the drive. After the cartridgehas been extracted from the drive, the elevator 750 is used to positionthe housing 1082 and the grasped cartridge for insertion into anotherone of the drives 210.

[0254] With reference to FIGS. 36A-36G, having generally described theuse of the cartridge transport 214 in moving a data cartridge between amagazine and a drive, the operation of the picker assembly 1164 (whichis comprised of the finger/thumb assembly 1168 and the finger actuationassembly 1170) and the linear drive assembly 1162 is described withrespect to the: (a) picking or removing of a cartridge from a magazine;and (b) loading of a previously grasped cartridge into the magazine.FIGS. 36A-36F, when viewed in sequence, illustrate the operation of thepicker assembly 1164 and the linear drive assembly 1162 in picking anLTO cartridge 1244 with a picker notch 1242 from a magazine 1244. Withreference to FIG. 36A, (a) the elevator 750, horizontal transport unit1052, and rotary assembly 1086 have, as needed, positioned the housing1082 so that the opening 1084B is adjacent to the cartridge 1240; (b)the linear drive assembly 1162 has positioned the finger/thumb assembly1168 within the housing 1082; and (c) the finger actuation assembly 1164has positioned the picker 1218 so that the picker 1218 essentially hasno effect upon the finger 1202 during the extraction operation. Morespecifically, the solenoid 1224 has fully extended the plunger 1226. Asa consequence, the picker 1218 is positioned such that further rotationis prevented by the stop 1228.

[0255] With reference to FIG. 36B, the DC motor 1176 of the linear driveassembly 1162 has been used to displace the finger/thumb assembly 1168along the lead screw 1174 and towards the cartridge 1240. At this point,the finger 1202 has engaged the top end of the cartridge 1240. Withreference to FIG. 36C, as the linear drive assembly 1162 displaces thefinger/thumb assembly 1168 further towards the cartridge 1240, theinteraction of the finger 1202 with the surfaces of the cartridge 1240causes the finger 1202 to rotate away from the cartridge 1240 such thatenergy is stored in the return spring 1210. With reference to FIGS. 36Cand 36D, further displacement of the finger/thumb assembly 1168 towardsthe cartridge 1240 eventually results in the finger 1202 reaching thenotch 1242. At this point, the energy stored in the return spring 1210causes the finger 1202 to engage the notch 1242. With the notch 1242engaged, the cartridge 1240 can now be extracted from the magazine 1244.With reference to FIG. 36E, after the notch 1242 has been engaged, thelinear drive assembly 1162 operates so as to displace the finger/thumbassembly 1168 and the cartridge 1240 away from the magazine 1244. Thewall 1230 serves to counteract rotation of the cartridge 1240 during theextraction. The linear drive assembly 1162 continues the displacement ofthe finger/thumb assembly 1168 and the cartridge 1240 away from themagazine 1244 until the cartridge is fully within the housing 1082, asshown in FIG. 36F.

[0256]FIGS. 36F, 36E, 36D and 36G illustrate the operation of the pickerassembly 1164 and the linear drive assembly 1162 in loading the LTOcartridge 1244 into the magazine 1244. With reference to FIG. 36F, (a)the elevator 750, horizontal transport unit 1052, and rotary assembly1086 have, as needed, positioned the housing 1082 so that the opening1084B is adjacent to the slot of the magazine 1244 which is to hold thecartridge 1240; (b) the linear drive assembly 1162 and the finger/thumbassembly 1168 are operating to retain the cartridge 1240 within thehousing 1082; and (c) the finger actuation assembly 1164 has positionedthe picker 1218 so that the picker 1218 will not have an effect upon thefinger 1202 during insertion of the cartridge 1240 into the magazine1244. More specifically, the solenoid 1224 has fully extended theplunger 1226. As a consequence, the picker 1218 is positioned such thatfurther rotation is prevented by the stop 1228.

[0257] With reference to FIG. 36E, the linear drive assembly 1162 hasbeen used to displace the finger/thumb assembly 1168 and the cartridge1240 along the lead screw 1174 and towards the magazine 1244. Withreference to FIG. 36D, the linear drive assembly 1162 has continued todisplace the finger/thumb assembly 1168 and the cartridge 1240 along thelead screw 1174 and towards the magazine 1244 until the cartridge 1240is fully loaded into the magazine 1244. During the displacement of thecartridge 1240 towards the magazine 1244, the wall 1230 has served tocounteract rotation of the cartridge 1240. At this point, the picker camsurface 1220 of the picker 1218 is disposed between the finger cam 1206of the finger 1202 and the pivot shaft 1204 of the finger 1202. Todisengage the finger 1202 from the notch 1242 of the cartridge 1240 andrelease the cartridge 1240, the solenoid 1224 is operated so as toretract the plunger 1226 and thereby rotate the picker 1218. Rotation ofthe picker 1218 pushes the finger 1202 away from the cartridge 1240 asshown in FIG. 36G. At this point, loading of the cartridge 1240 into themagazine 1244 is complete.

[0258]FIGS. 37A-37D, when viewed in sequence, illustrate the operationof the picker assembly 1164 and the linear drive assembly 1162 inloading the LTO cartridge 1244 into a drive 1246. With reference to FIG.37A, (a) the elevator. 750, horizontal transport unit 1052, and rotary1086 have, as needed, positioned the housing 1082 so that the opening1084B is adjacent to the receptacle of the drive 1246; (b) the lineardrive assembly 1162 and the finger/thumb assembly 1168 are operating toretain the cartridge 1240 within the housing 1082; and (c) the fingeractuation assembly 1164 has positioned the picker 1218 so that thepicker 1218 will not have an effect upon the finger 1202 at this pointin time. More specifically, the solenoid 1224 has fully extended theplunger 1226. As a consequence, the picker 1218 is positioned such thatfurther rotation is prevented by the stop 1228.

[0259] With reference to FIG. 37B, the linear drive assembly 1162 hasbeen used to displace the finger/thumb assembly 1168 and the cartridge1240 along the lead screw 1174 and towards the drive 1246. In addition,before the displacement of the finger/thumb assembly 1168 along the leadscrew 1174 by the linear drive assembly 1162 reaches a point at whichthe finger cam 1206 of the finger 1202 could contact with the picker camsurface 1220, the finger actuation assembly 1164 has positioned thepicker 1218 the picker 1218 so that the picker cam surface 1220 willcause the finger to rotate away from the cartridge 1240 and release thecartridge earlier than occurs during the loading of a cartridge into amagazine. More specifically, the solenoid 1224 has been operated so asto fully retract the plunger 1226 and thereby position the picker camsurface 1220 of the picker 1218 to interact with the finger cam 1206 ofthe finger 1202 to release the cartridge earlier than in the magazineloading operation. With reference to FIGS. 37C and 37D, furtherdisplacement of the picker/thumb assembly 1168 by the linear driveassembly 1162 eventually causes the picker cam surface 1220 to engagethe finger cam 1206. After the picker cam surface 1220 has engaged thefinger cam 1206, further displacement of the picker/thumb assembly 1168towards the drive results in the picker cam surface 1220 applying aforce to the finger 1202, via the finger cam 1206, that causes thefinger 1202 to rotate about the pivot shaft 1204 and away from thecartridge 1240, thereby releasing the cartridge 1240 to the drive 1246.Comparison of FIG. 37C to FIG. 36G shows that the operation of thefinger actuation assembly 1164 in the loading of the cartridge 1240 intothe drive 1246 causes the finger 1202 to release the cartridge 1244earlier than in the case of loading the cartridge 1244 into the magazine1244.

[0260]FIGS. 37E, 37F, 37G and 37A, when viewed in sequence, illustratethe operation of the picker assembly 1164 and the linear drive assembly1162 in picking an LTO cartridge 1244 with a picker notch 1242 from thedrive 1246. With reference to FIG. 37E, (a) the elevator 750, horizontaltransport unit 1052, and rotary assembly 1086 have, as needed,positioned the housing 1082 so that the opening 1084B is adjacent to thedrive 1246; (b) the linear drive assembly 1162 has positioned thefinger/thumb assembly 1168 within the housing 1082; and (c) the fingeractuation assembly 1164 has positioned the picker 1218 so that thepicker 1218 essentially has no effect upon the finger 1202 during theextraction operation. More specifically, the solenoid 1224 has fullyextended the plunger 1226. As a consequence, the picker 1218 ispositioned such that further rotation is prevented by the stop 1228.

[0261] With reference to FIG. 37F, the DC motor 1176 of the linear driveassembly 1162 has been used to displace the finger/thumb assembly 1168along the lead screw 1174 and towards the drive 1246. At this point, thefinger 1202 has engaged the cartridge 1240 and the interaction of thefinger 1202 with the surfaces of the cartridge 1240 has caused thefinger 1202 to rotate away from the cartridge 1240 such that energy isstored in the return spring 1210. With reference to FIG. 37G, furtherdisplacement of the finger/thumb assembly 1168 towards the cartridge1240 eventually results in the finger 1202 reaching the notch 1242. Atthis point, the energy stored in the return spring 1210 causes thefinger 1202 to engage the notch 1242. With the notch 1242 engaged, thecartridge 1240 can now be extracted from the drive 1246. With referenceto FIG. 37A, after the notch 1242 has been engaged, the linear driveassembly 1162 operates so as to displace the finger/thumb assembly 1168and the cartridge 1240 away from the drive 1246. The linear driveassembly 1162 continues the displacement of the finger/thumb assembly1168 and the cartridge 1240 away from the magazine 1244 until thecartridge is fully within the housing 1082, as shown in FIG. 37A.

[0262] It should be appreciated that many of the elements of the library202 employed linear or rotary actuators. Generally, for elements thatemploy a linear actuator, designs are feasible that employ a rotaryactuator. Similarly, for elements that employ a rotary actuator, designsare feasible that employ a linear actuator. Further, the elements of thelibrary 202 that employ a linear or rotary actuator, employ electricalactuators. Designs are feasible that employ actuators that utilizehydraulic or pneumatic actuators are feasible. In addition, many of theelectrical motors utilized in the library are DC motors. As should beappreciated, other types of electrical motors are feasible.

[0263] With reference to FIG. 38, the relationship between the spaceoccupied by shelved magazines in the library 202 to the other elementsof the library is described. A first magazine 1250A associated with afirst shelf 1252A of any one of the five columns of shelving 328Aresides in a vertical plane that is bounded by a first face 1254A thatcorresponds with the front face of the magazine and a second face 1256Athat corresponds with the rear face of the magazine and is substantiallyparallel to the first face 1254A (a first magazine space). Similarly, asecond magazine 1250B associated with a second shelf 1252B of any one ofthe two columns of shelving 328B resides in a vertical plane that isbounded by a first face 1254B and a second face 1256B that respectivelycorrespond to the front and rear surfaces of the second magazine 1250B(a second magazine space). The distance between the first and secondplanes 1254A, 1256A (or between the first and second planes 1254B,1256B) defines the minimum distance that is needed between the firstplanes 1254A, 1254B (at least a portion of the space between these twoplanes defining a magazine transport space) for the magazine transport212 to move a magazine within the library 202 without re-orienting themagazine. The closer the distance between the first planes 1254A, 1254Bis to the minimum distance, the more volume there is within the libraryto accommodate more data cartridges and/or more drives. In theillustrated embodiment, the distance between the planes 1254A, 1254B isless than twice the distance between the planes 1254A, 1256A andapproaches 130% of the distance of the distance between the planes1254A, 1256A. Further, the distance between the first and second planes1254A, 1256A (or the distance between the first and second planes 1254B,1256B) is roughly equal to the distance between the front and rearsurfaces 1258A, 1258B of a drive of the two columns of drives 210. Thisallows the drives and shelving to be positioned within the library 202so as to efficiently utilize the available space within the library 202.It should also be appreciated that the magazine transport space overlapswith the space the magazine spaces, due to engagement of magazines bythe magazine transport 212.

[0264] In a magazine-based library with a circular/cylindrical typelayout, the magazine transport travels in a space that is locatedbetween two concentric “planes” or surfaces. Further, the magazines aretypically located in one or more spaces that are each located betweentwo planes.

[0265]FIG. 39 illustrates the control system 218 for the library 202.Generally, the control system 218 is comprised of controller 1264 thatis capable with communicating with other controllers in the library 202that are associated with various electrical elements within the library.More specifically, the controller 1264 is capable of communicating with:(a) a first and second entry/exit port controllers 1266A, 1266B thatrespectively control electrical elements associated with the first andsecond entry/exit ports 368, 370; (b) a horizontal axis controller 1268that controls electrical elements associated with the horizontal axisassembly 754 of the elevator 750; (c) a vertical axis controller 1270that controls electrical elements associated with the vertical axisassembly 752 of the elevator 750; (d) a short axis/magazine controller1272 that controls electrical elements associated with the horizontaltransport unit 1052, magazine picker 880, and magazine transport device900; (e) a rotation axis/picker axis controller 1274 that controlselectrical elements associated with the rotary 1086, the linear driveassembly 1162, and the picker assembly 1164; and (f) an environmentalcontroller 1276 that controls, among other things, the fans 220. Inaddition, the controller 1264 also communicates with elements associatedwith the operator interface 342. Further, the controller 1264 alsocommunicates with the QIP associated with an drive bay assembly 540 inthe library via a controller area network (CAN). Other control systemsare also feasible.

[0266] The library 202 operates to read and/or write data on a recordingmedium that is located in a cartridge that is stored in a magazine thatis, in turn, stored on a shelf or in another storage location. Further,when the cartridge is stored in the magazine, the cartridge is orientedin the library 202 such that the face of the cartridge with the greatestsurface area lies in a substantially vertical plane. Moreover, thecartridge is oriented so that the surface vector of the face of thecartridge with the greatest surface area is substantially parallel tothe direction in which the magazine picker 880 displaces the magazine.Further, when the cartridge picker 214 extracts/inserts the cartridgefrom/into the magazine, the cartridge picker 214 displaces the cartridgevertically within the noted vertical plane.

[0267] It should be appreciated that other embodiments of amagazine-based data cartridge library are capable of operating oncartridges that are oriented when in storage so that the face of thecartridge with the greatest surface area lies in a vertical plane, butthe surface vector of the face lies substantially perpendicular to thedirection in which a magazine picker displace the magazine storing thecartridge and/or a cartridge picker extracts/inserts the cartridgefrom/into the magazine such that the magazine is displaced horizontallywithin the vertical plane.

[0268]FIG. 40A illustrates an alternative embodiment of a magazine 1280suitable for use in an alternative embodiment of a magazine-based datacartridge library relative to library 202. When the magazine 1280 isoperationally disposed on a shelf 1282 of the library, the magazineholds a cartridge 1284 such that: (a) a face of the cartridge with thegreatest surface area 1286 lies in a vertical plane; (b) the surfacevector 1286 of the face 1286 is substantially perpendicular to adirection 1290 that the magazine is displaced by a magazine picker; and(c) the cartridge is displaced in a direction 1292, a verticaldirection, by a cartridge picker to insert/extract the cartridgeinto/from the magazine.

[0269]FIG. 40B illustrates an alternative embodiment of a magazine 1294suitable for use in an alternative embodiment of a magazine-based datacartridge library relative to library 202. Each of the features in FIG.40B that is substantially identical to a feature in FIG. 40A has beengive the same reference number as the feature in FIG. 40A. When themagazine 1294 is operationally disposed on a shelf 1282 of the library,the magazine holds a cartridge 1284 such that: (a) a face 1286 of thecartridge with the greatest surface area lies in a vertical plane; (b)the surface vector 1288 of the face 1286 is substantially parallel to adirection 1290 that the magazine is displaced by a magazine picker; and(c) the cartridge is displaced in a direction 1292, a horizontaldirection in the vertical plane in which the face of the cartridge withthe greatest surface area lies, by a cartridge picker to insert/extractthe cartridge into/from the magazine.

[0270]FIG. 40C illustrates an alternative embodiment of a magazine 1296suitable for use in an alternative embodiment of a magazine-based datacartridge library relative to library 202. Each of the features in FIG.40C that is substantially identical to a feature in FIG. 40A has beengive the same reference number as the feature in FIG. 40A. When themagazine 1296 is operationally disposed on a shelf 1282 of the library,the magazine holds a cartridge 1284 such that: (a) a face 1286 of thecartridge with the greatest surface area lies in a vertical plane; (b)the surface vector 1288 of the face 1286 is substantially perpendicularto a direction 1290 that the magazine is displaced by a magazine picker;and (c) the cartridge is displaced in a direction 1292, a horizontaldirection in the vertical plane in which the face of the cartridge withthe greatest surface area lies, by a cartridge picker to insert/extractthe cartridge into/from the magazine.

[0271]FIG. 40D illustrates an alternative embodiment of a magazine 1298suitable for use in an alternative embodiment of a magazine-based datacartridge library relative to library 202. Each of the features in FIG.40D that is substantially identical to a feature in FIG. 40A has beengive the same reference number as the feature in FIG. 40A. When themagazine 1298 is operationally disposed on a shelf 1282 of the library,the magazine holds a cartridge 1284 such that: (a) a face 1286 of thecartridge with the greatest surface area lies in a vertical plane; (b)the surface vector 1288 of the face 1286 is substantially perpendicularto a direction 1290 that the magazine is displaced by a magazine picker;and (c) the cartridge is displaced in a direction 1292, a horizontaldirection in the vertical plane in which the face of the cartridge withthe greatest surface area lies, by a cartridge picker to insert/extractthe cartridge into/from the magazine.

[0272]FIG. 40E illustrates a cross-section of alternative embodiment ofa magazine 1300 suitable for use in an alternative embodiment of amagazine-based data cartridge library relative to library 202. Each ofthe features in FIG. 40E that is substantially identical to a feature inFIG. 40A has been give the same reference number as the feature in FIG.40A. When the magazine 1300 is operationally disposed on a shelf 1282 ofthe library, the magazine holds a cartridge 1284 such that: (a) a face1286 of the cartridge with the greatest surface area lies in a verticalplane; (b) the surface vector 1288 of the face 1286 is substantiallyperpendicular to or substantially parallel to a direction that themagazine is displaced by a magazine picker; and (c) the cartridge isdisplaced in a direction 1292, a direction in the vertical plane inwhich the face of the cartridge with the greatest surface area lies thathas both vertical and horizontal components, by a cartridge picker toinsert/extract the cartridge into/from the magazine.

[0273]FIG. 40F illustrates a cross-section of alternative embodiment ofa magazine 1302 suitable for use in an alternative embodiment of amagazine-based data cartridge library relative to library 202. Each ofthe features in FIG. 40F that is substantially identical to a feature inFIG. 40A has been give the same reference number as the feature in FIG.40A. When the magazine 1302 is operationally disposed on a shelf 1282 ofthe library, the magazine holds a cartridge 1284 such that: (a) a face1286 of the cartridge with the greatest surface area lies in a verticalplane; (b) the surface vector 1288 of the face 1286 is substantiallyperpendicular or substantially parallel to a direction that the magazineis displaced by a magazine picker; and (c) the cartridge displaced in adirection 1292, a direction in the vertical plane in which the face ofthe cartridge with the greatest surface area lies that has both verticaland horizontal components, by a cartridge picker to insert/extract thecartridge into/from the magazine.

[0274] With reference to FIG. 41A-41B, an alternative embodiment of amagazine 1306 is suitable for use with an alternative embodiment of amagazine-based data cartridge library relative to library 202. Each ofthe features in FIGS. 41A-41B that is substantially identical to afeature in FIG. 40A has been give the same reference number as thefeature in FIG. 40A. When the magazine 1304 is operationally disposed ona shelf 1282 of the library, the magazine holds a cartridge 1284 suchthat: (a) a face 1286 of the cartridge with the greatest surface arealies in a vertical plane; (b) the surface vector 1288 of the face 1286is neither perpendicular or parallel to a direction that the magazine isdisplaced by a magazine picker; and (c) the cartridge is displaced in adirection 1292, a horizontal direction in the vertical plane in whichthe face of the cartridge with the greatest surface area lies, by acartridge picker to insert/extract the cartridge into/from the magazine.

[0275] Also feasible is a magazine that holds cartridge in a verticalplane and in an orientation that is a combination of the orientationsthat magazine 1300 or magazine 1302 and magazine 1304 hold a cartridge.

[0276] It should be appreciated that the foregoing magazine designs areonly exemplary of magazine designs that operatively hold magazines in amagazine-based data cartridge library in an orientation such that theface of the cartridge with the greatest surface area lies in a verticalplane.

[0277] It should also be appreciated that the library 202 is alsooperable with magazines that hold cartridges such that the face of acartridge with the greatest surface area does not lie in a verticalplane. With reference to FIG. 41, the library 202 is operable with amagazine 1306, shown in cross-section, that when supported on a shelf1282 in the library 202, the cartridge resides in a plane that isbetween a vertical plane and a horizontal plane. Further, the cartridgetransport 214 displaces the cartridge in this plane duringinsertion/extraction into/from the magazine. As side loading/unloadingembodiment of the magazine is also feasible but would not be operablewith the library 202 without modification. These magazine designs areonly exemplary of magazine designs suit for use magazine-based datacartridge library.

[0278] With reference to FIGS. 43A-43B, the expansion of themagazine-based data cartridge library 202 to include an add-on unit 1310is discussed. Generally, the library 202 is capable of being expanded toinclude drive and/or magazine storage capability beyond that availablein the library 202. The process of expanding the library 202 comprisesobtaining the add-on unit 1310. The add-on unit 1310 can have any of anumber of combinations of elements. For example, the add-on unit 1310may be comprised entirely of shelving for storing magazines, entirely ofdrives or drive bay assemblies for accommodating drives, and variouscombinations of shelving and drives or drive bay assemblies. The add-onunit 1310 can also comprise an entry/exit port. The add-on unit 1310 canalso be another magazine-based data cartridge library that is capable offunctioning independently of the library 202.

[0279] With reference to FIG. 43B, the process of making the expandedlibrary is described from a schematic perspective. The library 202 has amagazine transporter space 1312 and a side 340 that is capable of beingremoved or modified so as to provide a path for transporting magazinesbetween the library 202 and the add-on unit 1310. Located within themagazine transporter space 1312 are horizontally extending componentsthat are associated with the magazine transporter 212 and arecumulatively represented as horizontal components 1314. One horizontallyextending component is the guide shaft 780. Other embodiments may employa different type of rail or use a rack in a rack-and-pinion type ofdevice for moving a magazine picker. The add-on unit 1310 has a magazinetransporter space 1316 and may or may not have horizontally extendingcomponents. If the add-on unit 1310 has such components they arecumulatively represented by horizontal components 1318. Generally, theadd-on unit 1310 also has a side 1320 that is either removable orcapable of being altered to expose the magazine transport space.Alternatively, the add-on unit 1310 may be built or designed so that themagazine space is exposed and no removal or alteration of a side isnecessary.

[0280] The process of expanding the library 202 further comprises: (a)removing or modifying the side 340 of the library 202 to expose themagazine transporter space 1312 of the library; (b) removing oraltering, if necessary, the side 1320 of the add-on unit 1300 to exposethe magazine transporter space 1316; (c) aligning the magazinetransporter space 1312 of the library 202 with the magazine transporterspace 1316 of the add-on 1310; and (d) replacing the horizontalcomponents 1314 of the elevator of the library 202 that limit thehorizontal movement of the magazine transport 212 and any horizontalcomponents 1318 associated with the add-on 1310 that limit thehorizontal movement of a magazine transported within the add-on withcomponents that allow the magazine transport 212 to move within themagazine transporter space 1312 of the library 202, as well as themagazine transporter space 1316 of the add-on 1310. With respect to thereplacing step, the guide shaft 780 is replaced with a single,continuous guide shaft that allows the magazine transport to function inthe magazine transporter space 1312 of the library 202 and the magazinetransporter space 1306 of the add-on 1310, and thereby form an expandedlibrary 1322.

[0281] With reference to FIG. 44A, an alternative approach to replacinga guide shaft or other member that is used to horizontally displace amagazine picker is to effectively lengthen the rod or other member byadding one or more segments to the guide shaft or member. As shown inFIG. 44A, a magazine-based library 1326A comprises a magazine transportspace 1328A, a first magazine transport add-on space 1330A that istypically not used when the library 1326A is configured as a stand-alonedevice, a first side 1332A that is either removable or modifiable toprovide a path for a magazine transport to move between the firstlibrary 1326A and an add-on unit, and first horizontal magazinetransport components 1334A that are adapted to mate with comparablecomponents associated with the add-on unit. An add-on unit 1326Bcomprises a magazine transport space 1328B, a second magazine transportadd-on space 1330B, a second side 1332B that is either removable ormodifiable to provide a path for a magazine transport, and secondhorizontal magazine transport components 1334B that are adapted to matewith the first horizontal magazine components 1334A. In this embodiment,the first and second sides 1332A, 1332B are either removed orappropriately modified, the first and second magazine transport spaces1328A, 1328B are aligned, and the first and second horizontal magazinetransport components 1334A, 1334B are mated, thereby forming an expandedlibrary 1336.

[0282] With reference to FIG. 44B, another approach to replacing a guideshaft or other member that is used to horizontally displace a magazinepicker is to effectively lengthen the rod or other member by adding oneor more segments to the guide shaft or member. As shown in FIG. 44B, amagazine-based library 1340A comprises a magazine transport space 1342A,a first side 1344A that is either removable or modifiable to provide apath for a magazine transport to move between the library 1340A and anadd-on unit, and first horizontal magazine transport components 1346Athat are adapted to mate with a bridge components that, in turn, areadapted to mate with comparable components associated with the add-onunit. An add-on unit 1340B comprises a magazine transport space 1342B, asecond side 1344B that is either removable or modifiable to provide apath for a magazine transport, and second horizontal magazine transportcomponents 1346B that are adapted to mate with the bridge components. Inthis embodiment, the first and second sides 1344A, 1344B are eitherremoved or appropriately modified, the first and second magazinetransport spaces 1342A, 1342B are aligned, and the first and secondhorizontal magazine transport components 1346A, 1346B are mated to oneanother by an intermediate bridge component 1348, thereby forming theexpanded library 1350.

[0283] It should be appreciated that with respect to the various methodfor expanding a magazine-based data cartridge library exemplified inFIGS. 43B, 44A and 44B that further expansion of the magazine-based datacartridge library with additional add-on units is feasible.

[0284]FIGS. 45A-45E illustrate various embodiments of magazinepass-though ports that are each capable of passing a magazine between afirst magazine-based library 1354A with a first magazine transporter1356A and a second magazine-based library 1354B with a second magazinetransporter 1356B. With reference to FIG. 45A, a magazine pass-throughport 1358 is provided that allows the first magazine transporter 1356Ato move a magazine to and from a magazine storage space 1360 that isassociated with the second magazine-based library 1354B and accessibleby the second magazine transport 1356B.

[0285] With reference to FIG. 45B, a magazine pass-through port 1362 isprovided in which first and second magazine transporters 1356A, 1356Bare each able to access a space 1364 that is located between the firstand second libraries 1354A, 1354B and pass a magazine from one to theother using the space 1364.

[0286] With reference to FIG. 45C, a magazine pass-through port 1366 isprovided that utilizes an intermediate transport device 1368 to move amagazine between a first space 1370A that is accessible to a firstmagazine transporter 1356A and a second space 1370B that is accessibleto a second magazine transporter 1356B. Another embodiment uses a chuteto pass a magazine from a first space, such as the first space 1370A,associated with one library to a second such as the second space 1370B,associated with another library.

[0287] With reference to FIG. 45D, the first and second magazine-basedlibraries 1354A, 1354B are each magazine-based libraries with circularor cylindrical layouts. A magazine pass-through port 1372 is providedthat utilizes an intermediate transport device 1374 to move a magazinebetween a first space 1376A that is accessible to a first magazinetransporter 1356A and a second space 1376B that is accessible to thesecond magazine transporter 1356B. Alternatively, a magazine chute thatextends from the library 1354A to library 1354B can be used. A secondmagazine chute from library 1354B to library 1354A is also feasible.

[0288] With reference to FIG. 45E, the first and second magazine-basedlibraries 1354A, 1354B are each magazine-based libraries with circularor cylindrical layouts. A magazine pass-through port 1378 is providedthat utilizes an intermediate transport device in the form of a carouseldevice 1380 that is comprised of: (a) a carousel body 1382; and (b) apair of magazine bays 1384A, 1384B that are capable of accommodating amagazine and are each accessible to the first magazine transporter 1356Aand the second magazine transporter 1356B depending upon the rotationalposition of the carousel 1380. A carousel with one or more than two baysis feasible. The carousel device also comprises an electric motor (notshown) that is used to rotate the carousel body 1382 about an axis 1386as needed.

1. A magazine-based data cartridge library comprising: a frame; a shelfsystem, operatively attached to said frame, for supporting at least twodata cartridge magazines and comprising at least one shelf; a drive thatis operatively attached to said frame; a cartridge transport device,operatively attached to said frame, for moving a data cartridge betweena data cartridge magazine and said drive; a magazine transport device,operatively attached to said frame, for moving a data cartridgemagazine; and an operator alterable space located with a space definedby said frame; wherein said operator alterable space comprises a librarymounting structure for receiving a module, a first side that is exposedto said cartridge transport device and a second side that allows anoperator to attach a module to said mounting structure.
 2. Amagazine-based data cartridge library, as claimed in claim 1, furthercomprising: a magazine bay assembly module comprising: a housing thatdefines an interior space that is capable of accommodating a datacartridge magazine and an opening for receiving a data cartridgemagazine; said housing structure comprising a magazine bay mountingstructure for interfacing with said library mounting structure such thatwhen said magazine bay assembly module is mounted within said spacedefined by said frame, said opening is exposed to at least one of saidmagazine transport device and said cartridge transport device.
 3. Amagazine-based data cartridge library, as claimed in claim 2, wherein:said magazine bay assembly module comprising a bay guide that is locatedwithin said housing and capable of cooperating with a magazine guide fororienting a data cartridge magazine within said housing.
 4. Amagazine-based data cartridge library, as claimed in claim 2, wherein:said magazine bay assembly comprising a plurality of bays; wherein eachof said plurality of bays is capable of accommodating a data cartridgemagazine.
 5. A magazine-based data cartridge library, as claimed inclaim 1, further comprising: a drive bay assembly module comprising: ahousing structure that defines a first open side, a second open side,and a passageway extending between said first and second open sides;said housing structure comprising a drive bay mounting structure forinterfacing with said library mounting structure such that when saiddrive bay assembly module is mounted within said space defined by saidframe, said first open side is exposed to said cartridge transportdevice and said second open side is exposed to said space that isoperator accessible; a housing plug that is attached to said housing andfaces said second open side; and a sled for holding a drive that has afront side with a receptacle for receiving a data cartridge and a backside with a plug interface for receiving electrical signals; said sledcomprising: a sled frame that extends from a first end to a second endand is capable of holding a drive such that the receptacle of a drive isadjacent to said first end and the plug interface of the drive isadjacent to said second end; and electrical connection means forestablishing an electrical connection between the plug interface of adrive and a sled plug that faces toward said first end of said sled andis capable of mating with said housing plug; wherein when said sled ispositioned in said passageway such that said first end of said frame isadjacent to said first open side and said second end of said frame isadjacent to said second open side, said housing plug faces said sledplug.
 6. A magazine-based data cartridge library, as claimed in claim 1,further comprising: a drive bay assembly comprising: a housing structurethat defines a first open side, a second open side, and a plurality ofdrive bays, each extending between said first and second open sides;said housing structure comprising a drive bay mounting structure forinterfacing with said library mounting structure such that when saiddrive bay assembly module is mounted within said space defined by saidframe, said first open side is exposed to said cartridge transportdevice and said second open side is exposed to said space that isoperator accessible; a plurality of housing plugs that are each attachedto said housing and face said second open side, wherein one of saidplurality of plugs is associated with each of said plurality of drivebays; a plurality of sleds, each capable of holding a drive that has afront side with a receptacle for receiving a data cartridge and a backside with a plug interface for receiving electrical signals; whereineach of said plurality of sleds comprising an electrical connectionmeans for establishing an electrical connection between the pluginterface of a drive and a sled plug that is capable of mating with oneof said plurality of housing plugs.
 7. A magazine-based data cartridgelibrary, as claimed in claim 6, wherein: said drive bay assemblycomprising a processor, attached to said housing, for distributingelectrical signals to each of said plurality of housing plugs.
 8. Amagazine-based data cartridge library, as claimed in claim 7, wherein:said housing comprising a processor bay for holding said processor;wherein said processor bay defining an opening that is exposed to aspace that is operator accessible.
 9. A magazine-based data cartridgelibrary, as claimed in claim 8, wherein: said processor comprising ahandle for facilitating insertion/removal of a portion of said processorthrough said opening.